9 October 2026 · DMARC Engine · 33 min read
Navigating Email Authentication Across Multiple Departments
When dealing with email authentication for domains with complex organisational structures, one of the most significant challenges is navigating the requirements of multiple departments. Each department may have its own email infrastructure, third-party services, and authentication needs, which can make it difficult to implement a cohesive email authentication strategy. For instance, a university may have separate departments for student admissions, alumni relations, and research, each with its own email domain and infrastructure.
In such cases, it is essential to have a centralised email authentication management system to ensure that all departments are aligned with the organisation's overall email authentication policy. A hosted or managed setup can be particularly useful in this scenario, as it allows for the centralised management of email authentication records, such as SPF, DKIM, and DMARC, across multiple departments.
For example, our team at DMARC Engine has worked with a large retail company that had multiple departments, each with its own email marketing campaigns. We helped them implement a centralised DMARC management system, which enabled them to monitor and manage email authentication across all departments from a single centre. This allowed them to identify and mitigate potential email authentication issues before they became major problems.
One of the key benefits of a centralised email authentication management system is that it enables organisations to maintain a consistent email authentication policy across all departments. This can help to prevent email authentication issues, such as SPF alignment problems, which can occur when different departments have different SPF records.
To illustrate this point, consider the following SPF record snippet:
v=spf1 include:_spf.example.com include:_spf.marketing.example.com -allIn this example, the SPF record includes two separate SPF records, one for the main domain (_spf.example.com) and one for the marketing department (_spf.marketing.example.com). This can create alignment issues if the marketing department's SPF record is not properly aligned with the main domain's SPF record.
A centralised email authentication management system can help to mitigate such issues by ensuring that all SPF records are properly aligned and consistent across all departments.
Another challenge of navigating email authentication across multiple departments is dealing with third-party services. Many organisations use third-party services, such as email marketing platforms, to send emails on their behalf. These services often require their own email authentication setup, which can add complexity to the overall email authentication strategy.
For instance, a company may use a third-party email marketing platform to send newsletters to its customers. This platform may require its own DKIM key, which needs to be configured and managed separately from the company's main DKIM key.
To manage such scenarios, it is essential to have a clear understanding of the email authentication requirements of each third-party service and to ensure that these requirements are properly integrated into the overall email authentication strategy.
In a hosted or managed setup, this can be achieved by working closely with the email authentication provider to ensure that all third-party services are properly configured and managed.
For example, our team at DMARC Engine has worked with a company that used a third-party email marketing platform to send newsletters to its customers. We helped them configure and manage the DKIM key for this platform, ensuring that it was properly aligned with the company's main DKIM key.
In addition to managing third-party services, it is also essential to ensure that all departments are aware of the organisation's email authentication policy and are properly trained on how to implement and manage email authentication.
This can be achieved through regular training and awareness programmes, which can help to educate departments on the importance of email authentication and how to properly manage it.
For instance, our team at DMARC Engine provides regular training and support to our customers, helping them to understand and manage their email authentication setup.
By providing such training and support, organisations can ensure that all departments are properly equipped to manage email authentication and that the overall email authentication strategy is effective and consistent.
In short, navigating email authentication across multiple departments requires a centralised email authentication management system, a clear understanding of third-party services, and proper training and awareness programmes.
By implementing such measures, organisations can ensure that their email authentication strategy is effective, consistent, and aligned with their overall organisational goals.
In our experience, a hosted or managed setup can be particularly useful in such scenarios, as it allows for the centralised management of email authentication records and provides access to expert support and training.
Ultimately, the key to successful email authentication is to have a deep understanding of the organisational structure and email infrastructure, as well as the ability to adapt and evolve the email authentication strategy as the organisation grows and changes.
By taking a proactive and centralised approach to email authentication, organisations can optimise their email deliverability, prevent email authentication issues, and ensure that their emails are properly authenticated and delivered to their intended recipients.
The Challenges of Implementing DMARC in Subsidiaries
Implementing DMARC in subsidiaries can be a complex task, particularly when dealing with multiple domains, subdomains, and organisational structures. One of the primary challenges is ensuring that all subsidiaries are aligned with the parent company's email authentication policies. For instance, a company like BBC may have multiple subsidiaries such as BBC Studios, BBC News, and BBC Sport, each with their own domain and email infrastructure. In a hosted setup, such as the one we manage at DMARC Engine, we often see customers struggling to keep track of all the different domains and subdomains that need to be configured for DMARC.
A common issue we encounter is the use of subdomains for different departments or regions within a subsidiary. For example, a company like Tesco may have subdomains like uk.tesco.com, us.tesco.com, and au.tesco.com for their different regional operations. Each of these subdomains may have its own email infrastructure, making it difficult to implement DMARC across all of them. To overcome this challenge, we recommend using a wildcard DMARC record, such as:
_dmarc.tesco.com. IN TXT "v=DMARC1; p=reject; pct=100; rua=mailto:rua@dmarc.tesco.com; ruf=mailto:ruf@dmarc.tesco.com; fo=1"This record will apply to all subdomains of tesco.com, making it easier to manage DMARC across the organisation.
Another challenge we see is the use of third-party services by subsidiaries, which can make it difficult to authenticate emails. For example, a company like Barclays may use a third-party service like Salesforce to send emails on their behalf. In this case, the third-party service may not be aligned with the parent company's email authentication policies, which can lead to authentication failures. To overcome this challenge, we recommend using a DMARC record with a relaxed policy, such as:
_dmarc.barclays.com. IN TXT "v=DMARC1; p=none; pct=100; rua=mailto:rua@dmarc.barclays.com; ruf=mailto:ruf@dmarc.barclays.com; fo=1"This record will allow emails from third-party services to be delivered, while still providing visibility into authentication results through the aggregate reports.
In addition to these challenges, we also see issues with DKIM key management in subsidiaries. For example, a company like HSBC may have multiple DKIM keys for different subdomains, which can make it difficult to manage and rotate these keys. To overcome this challenge, we recommend using a centralised DKIM key management system, such as the one we provide at DMARC Engine. This system allows customers to easily manage and rotate their DKIM keys, ensuring that their emails are always authenticated correctly.
In terms of trade-offs, one of the main decisions that needs to be made when implementing DMARC in subsidiaries is the level of control to give to each subsidiary. On the one hand, giving each subsidiary full control over their DMARC configuration can make it easier for them to manage their own email infrastructure. On the other hand, this can also lead to inconsistencies in email authentication policies across the organisation, which can increase the risk of authentication failures. To overcome this challenge, we recommend using a centralised management system, such as the one we provide at DMARC Engine, which allows customers to set policies and monitor authentication results across all subsidiaries.
Finally, Notably, implementing DMARC in subsidiaries can also have implications for email deliverability. For example, if a subsidiary has a poor reputation due to spam or phishing activities, this can affect the deliverability of emails from other subsidiaries. To overcome this challenge, we recommend monitoring email authentication results and reputation across all subsidiaries, and taking action to address any issues that arise. By doing so, organisations can ensure that their emails are always delivered to the inbox, and that their brand reputation is protected.
In our experience, a hosted or managed setup can greatly simplify the process of implementing DMARC in subsidiaries. For example, at DMARC Engine, we provide a centralised management system that allows customers to set policies, monitor authentication results, and manage DKIM keys across all subsidiaries. This can help to ensure that email authentication policies are consistent across the organisation, and that emails are always delivered to the inbox. Also, our system provides detailed reporting and analytics, which can help organisations to identify and address any issues with email authentication or deliverability. By using a hosted or managed setup, organisations can optimise their email deliverability, and ensure that their brand reputation is protected.
Managing SPF Records for Acquired Domains
When a company acquires another organisation, managing SPF records can become a complex task, especially if the acquired domain has its own set of email infrastructure and third-party services. The key challenge is to ensure that the acquired domain's email authentication is properly set up to prevent spam filters from flagging emails as unauthenticated. In our experience at DMARC Engine, we have seen cases where acquired domains have outdated or missing SPF records, leading to email deliverability issues.
One common issue we encounter is when the acquired domain has a large number of third-party services sending emails on its behalf, such as marketing automation tools or customer support platforms. In such cases, it is essential to identify all the IP addresses and domains used by these services and include them in the SPF record. For example, let's say the acquired domain is example.co.uk and it uses a marketing automation tool with the domain mailer.example.co.uk. The SPF record for example.co.uk would need to include the IP addresses of the marketing automation tool, as shown in the following example:
example.co.uk. 3600 IN TXT "v=spf1 include:mailer.example.co.uk ip4:192.0.2.1 ip4:192.0.2.2 -all"In this example, the SPF record includes the mailer.example.co.uk domain, which has its own set of IP addresses, as well as two specific IP addresses (192.0.2.1 and 192.0.2.2) that are used by the marketing automation tool.
Another challenge we face is when the acquired domain has a complex email infrastructure, with multiple mail servers and relays. In such cases, it is crucial to ensure that all mail servers and relays are included in the SPF record to prevent email deliverability issues. For instance, let's say the acquired domain example.co.uk has two mail servers, mail1.example.co.uk and mail2.example.co.uk, and a relay server relay.example.co.uk. The SPF record for example.co.uk would need to include all these servers, as shown in the following example:
example.co.uk. 3600 IN TXT "v=spf1 mx ip4:192.0.2.1 ip4:192.0.2.2 include:relay.example.co.uk -all"In this example, the SPF record includes the mx mechanism, which covers the mail servers mail1.example.co.uk and mail2.example.co.uk, as well as the IP addresses of these servers (192.0.2.1 and 192.0.2.2) and the relay.example.co.uk domain.
In a hosted or managed setup, such as the one offered by DMARC Engine, managing SPF records for acquired domains can be simplified through the use of automated tools and expert guidance. For example, our platform provides a centralised dashboard for managing SPF records, which allows administrators to easily add or remove IP addresses and domains, as well as monitor email deliverability issues. Also, our team of experts can provide guidance on how to set up SPF records for acquired domains, taking into account the specific email infrastructure and third-party services used by the organisation.
To optimise SPF record management for acquired domains, we recommend the following best practices:
- Conduct a thorough audit of the acquired domain's email infrastructure and third-party services to identify all IP addresses and domains that need to be included in the SPF record.
- Use a centralised dashboard or tool to manage SPF records, such as the one offered by DMARC Engine.
- Monitor email deliverability issues regularly and adjust the SPF record as needed to prevent spam filters from flagging emails as unauthenticated.
- Consider using a third-party service to help manage SPF records, especially if the organisation has a complex email infrastructure or multiple acquired domains.
By following these best practices and using the right tools and expertise, organisations can ensure that their acquired domains have properly set up SPF records, which is essential for preventing email deliverability issues and maintaining a good email reputation.
DKIM Key Management for Complex Organisational Structures
DKIM key management is a critical component of email authentication, particularly for organisations with complex structures, such as those with multiple departments, subsidiaries, or acquired domains. In our experience, managing DKIM keys for these organisations can be a daunting task, requiring careful planning and organisation to ensure seamless email deliverability.
One of the primary challenges is determining the optimal number of DKIM keys to use. While it may be tempting to use a single DKIM key across all departments and subsidiaries, this approach can lead to a number of issues, including reduced flexibility and increased risk in the event of a key compromise. For example, if a single DKIM key is used across all departments and a key compromise is detected, the organisation may need to rotate the key across all departments, which can be a time-consuming and resource-intensive process.
A better approach is to use a separate DKIM key for each department or subsidiary. This allows for greater flexibility and reduces the risk associated with key compromise. For instance, if a key compromise is detected in one department, the organisation can rotate the key for that department without affecting other departments.
However, using multiple DKIM keys also introduces additional complexity, particularly when it comes to key management and rotation. In our experience, it is essential to have a well-planned key management strategy in place to ensure that keys are properly rotated and updated. This can be achieved through the use of automated key management tools, such as those provided by hosted DMARC services.
For example, our hosted DMARC service provides automated DKIM key management, allowing organisations to easily generate, rotate, and update DKIM keys across all departments and subsidiaries. This not only simplifies the key management process but also reduces the risk of human error.
When it comes to DKIM key rotation, there are a number of factors to consider. The frequency of rotation will depend on the organisation's specific needs and risk tolerance. As a general rule, we recommend rotating DKIM keys every 6-12 months. However, this may need to be more frequent for organisations with high-risk profiles or those that require more stringent security controls.
In addition to rotation frequency, it is also essential to consider the impact of key rotation on email deliverability. When a DKIM key is rotated, there is a risk that emails may be delayed or rejected by receivers if the new key is not properly configured. To mitigate this risk, we recommend implementing a staggered key rotation approach, where the new key is introduced in parallel with the existing key. This allows receivers to learn the new key without disrupting email deliverability.
Here is an example of a staggered key rotation approach using a selector record:
selector1._domainkey.example.com. IN TXT "k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4hV+9RzKkTjT2l4jHc8xOxziPb5CJjQxN7k8xMm1Df+ZK9x+6T5r5Y7zK5rK4rK3xOx5T5rK4rK3xOx5T5rK4rK3xO"
selector2._domainkey.example.com. IN TXT "k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8hV+9RzKkTjT2l4jHc8xOxziPb5CJjQxN7k8xMm1Df+ZK9x+6T5r5Y7zK5rK4rK3xOx5T5rK4rK3xOx5T5rK4rK3xO"In this example, selector1 is the existing key and selector2 is the new key. By introducing the new key in parallel with the existing key, receivers can learn the new key without disrupting email deliverability.
Another important consideration is the size of the DKIM key. While larger keys provide greater security, they also increase the risk of compatibility issues with older systems. In our experience, a key size of 2048 bits is a good balance between security and compatibility. However, this may need to be adjusted depending on the organisation's specific needs and risk tolerance.
For example, organisations that require more stringent security controls may need to use larger keys, such as 4096 bits. However, this may require additional testing to ensure compatibility with older systems.
In addition to key size, it is also essential to consider the algorithm used to generate the DKIM key. The most common algorithm used is RSA, which is widely supported by most email systems. However, other algorithms, such as ECDSA, may be more suitable for organisations with specific security requirements.
Here is an example of a DKIM key record using the ECDSA algorithm:
example._domainkey.example.com. IN TXT "k=ecdsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4hV+9RzKkTjT2l4jHc8xOxziPb5CJjQxN7k8xMm1Df+ZK9x+6T5r5Y7zK5rK4rK3xOx5T5rK4rK3xO"In this example, the k parameter specifies the algorithm used to generate the key, which in this case is ECDSA.
In conclusion to this section on DKIM key management, it is clear that managing DKIM keys for complex organisational structures requires careful planning and organisation. By using a separate DKIM key for each department or subsidiary, rotating keys regularly, and considering key size and algorithm, organisations can ensure seamless email deliverability while minimising the risk of key compromise. As a hosted DMARC service provider, we have seen firsthand the importance of proper DKIM key management, and we recommend that organisations prioritise this critical component of email authentication.
To centre the DKIM key management process, organisations should consider implementing automated key management tools, such as those provided by hosted DMARC services. These tools can simplify the key management process, reduce the risk of human error, and ensure that keys are properly rotated and updated. By optimising the DKIM key management process, organisations can improve email deliverability, reduce the risk of key compromise, and ensure the security and integrity of their email communications.
In our experience, the colour of the DKIM key management process can vary depending on the organisation's specific needs and risk tolerance. However, by prioritising proper DKIM
A Step-by-Step Guide to Configuring MTA-STS
Configuring MTA-STS can be a complex process, particularly for domains with complex organisational structures. As an email-deliverability engineer, I have seen firsthand the challenges that come with implementing MTA-STS in a large-scale organisation. In this section, I will provide a step-by-step guide to configuring MTA-STS, highlighting the key considerations and trade-offs that need to be taken into account.
Firstly, it is essential to understand the requirements for MTA-STS. The protocol requires a valid TLS certificate, a TXT record, and an HTTPS endpoint. The TXT record should contain the following information:
_mta-sts.example.com. IN TXT "v=STSv1; id=1234567890"The id field is used to identify the policy, and it should be unique for each domain. In a hosted or managed setup, this id field is often automatically generated and managed by the provider.
The next step is to configure the HTTPS endpoint. This endpoint should serve a policy file that contains the MTA-STS policy. The policy file should be in JSON format and should contain the following information:
{
"version": "STSv1",
"mode": "enforce",
"mx": [
"mx1.example.com",
"mx2.example.com"
],
"max_age": 86400
}The mode field can be set to either testing, enforce, or none. The testing mode is used to test the MTA-STS configuration without enforcing it, while the enforce mode is used to enforce the policy. The none mode is used to disable MTA-STS.
The mx field should contain a list of authorised mail servers. These mail servers should have valid TLS certificates and should be configured to use the same domain name as the MTA-STS policy.
The max_age field specifies the maximum age of the policy in seconds. This field is used to determine how often the policy should be refreshed.
Once the policy file is created, it should be served over HTTPS. The HTTPS endpoint should be configured to use a valid TLS certificate and should be accessible from the internet. In a hosted or managed setup, the HTTPS endpoint is often automatically configured and managed by the provider.
One of the key considerations when configuring MTA-STS is the impact on email deliverability. MTA-STS can help to prevent email spoofing and improve email deliverability, but it can also cause issues if not configured correctly. For example, if the MTA-STS policy is set to enforce mode and the mail server does not have a valid TLS certificate, emails may be rejected by the recipient's mail server.
To mitigate this risk, it is essential to test the MTA-STS configuration thoroughly before enforcing it. This can be done by setting the mode field to testing and monitoring the email deliverability. If any issues are encountered, the mode field can be set to none to disable MTA-STS until the issues are resolved.
In addition to testing the MTA-STS configuration, it is also essential to monitor the email deliverability regularly. This can be done by analysing the aggregate reports and adjusting the MTA-STS policy as needed. For example, if the aggregate reports show that emails are being rejected due to MTA-STS issues, the mode field can be set to testing to test the configuration and identify the issues.
In a complex organisational structure, it is also essential to consider the impact of MTA-STS on different departments and subsidiaries. For example, if a subsidiary has its own mail server, it may need to have its own MTA-STS policy. In this case, the parent organisation should ensure that the subsidiary's MTA-STS policy is aligned with its own policy to avoid any conflicts.
In conclusion to this section, configuring MTA-STS requires careful consideration of several factors, including the impact on email deliverability, the requirements for a valid TLS certificate, and the need to test and monitor the configuration regularly. By following the steps outlined in this section and considering the trade-offs and complexities involved, organisations can effectively configure MTA-STS to improve their email deliverability and prevent email spoofing. As an email-deliverability engineer, I recommend that organisations take a careful and considered approach to configuring MTA-STS, and seek expert advice if needed, to ensure that their email authentication is optimised and effective.
Real-World Examples of Email Authentication in Action
When dealing with domains that have complex organisational structures, email authentication can become a daunting task. In our experience at DMARC Engine, we have encountered numerous scenarios where organisations have struggled to implement and manage email authentication protocols such as DMARC, SPF, and DKIM. In this section, we will delve into some real-world examples of email authentication in action, highlighting the challenges, trade-offs, and best practices that organisations can learn from.
One common challenge we encounter is managing SPF records for acquired domains. For instance, consider a company that has acquired several smaller businesses, each with their own domain. In this scenario, the company needs to ensure that all the acquired domains are properly configured with SPF records to prevent spam and phishing attacks.
example.com. IN TXT "v=spf1 include:_spf.example.com -all"
_spf.example.com. IN TXT "v=spf1 ip4:192.0.2.1 ip4:192.0.2.2 include:mailgun.org -all"As shown in the above example, the company can create a centralised SPF record that includes all the IP addresses and domains of the acquired businesses. However, this approach requires careful management to ensure that all the IP addresses and domains are properly included and updated.
Another challenge we often see is implementing DMARC for subsidiaries. Consider a large conglomerate with multiple subsidiaries, each with their own domain. In this scenario, the conglomerate needs to ensure that all the subsidiaries are properly configured with DMARC records to prevent spam and phishing attacks.
_dmarc.example.com. IN TXT "v=DMARC1; p=reject; pct=100; rua=mailto:dmarc@example.com; ruf=mailto:dmarc@example.com; fo=1"As shown in the above example, the conglomerate can create a centralised DMARC record that applies to all the subsidiaries. However, this approach requires careful management to ensure that all the subsidiaries are properly configured and that the DMARC record is updated regularly.
DKIM key management is another area where organisations often struggle. Consider a company that has multiple email servers, each with their own DKIM key. In this scenario, the company needs to ensure that all the DKIM keys are properly managed and updated to prevent email spoofing.
default._domainkey.example.com. IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCqGKukO1De7zhZj6+H0qtjTkVxwTCpvKe4eCZ0FPqri0cb2JZfXJ/DgYSF6vUpwmJG8wVQZKjeGcjDOL5UlsuusFncCzWBQ7RKNUSesmQRMSGkVb1/3j+skZ6UtW+5u09lHNsj6tQ51s1SPrCBkedbNf0Tp0GbMJDyR4e9T04ZZwIDAQAB"As shown in the above example, the company can create a centralised DKIM key that applies to all the email servers. However, this approach requires careful management to ensure that all the DKIM keys are properly updated and rotated regularly.
In our experience, hosted or managed setups can greatly simplify email authentication management for complex organisational structures. For instance, our DMARC Engine platform provides a centralised dashboard for managing DMARC, SPF, and DKIM records, making it easier for organisations to configure and update their email authentication settings. Also, our platform provides automated reporting and analytics, allowing organisations to monitor their email authentication performance and make data-driven decisions.
One of the key benefits of using a hosted or managed setup is that it allows organisations to centralise their email authentication management, reducing the complexity and administrative burden associated with managing multiple domains and email servers. For example, our platform allows organisations to create a single DMARC record that applies to all their domains, making it easier to manage and update their email authentication settings.
However, there are also trade-offs to consider when using a hosted or managed setup. For instance, organisations may need to compromise on customisation and flexibility, as the hosted or managed setup may not provide the same level of control as a self-managed setup. Also, organisations may need to consider the cost and scalability of the hosted or managed setup, as it may not be suitable for very large or complex organisational structures.
In terms of best practices, we recommend that organisations take a phased approach to implementing email authentication, starting with a small pilot group and gradually rolling out to larger groups. This approach allows organisations to test and refine their email authentication settings, reducing the risk of errors or disruptions to email services. Also, we recommend that organisations regularly monitor and analyse their email authentication performance, using data and analytics to inform their decision-making and optimise their email authentication settings.
Overall, email authentication for domains with complex organisational structures requires careful planning, management, and monitoring. By using real-world examples and concrete recommendations, organisations can navigate the challenges of email authentication and ensure that their email services are secure, reliable, and compliant with industry standards. Whether using a hosted or managed setup, or a self-managed approach, organisations need to be aware of the trade-offs and best practices involved in email authentication management, and take a proactive and data-driven approach to optimising their email authentication settings.
Interpreting Aggregate Reports for Large-Scale Organisations
Interpreting aggregate reports, also known as RUA reports, is a critical task for organisations with complex structures, as it provides valuable insights into email authentication issues. These reports are generated by receivers, such as Gmail or Yahoo, and sent to the domain owner, containing data on email authentication results, including DMARC, SPF, and DKIM. For large-scale organisations, analysing these reports can be a daunting task, especially when dealing with multiple domains, subsidiaries, and departments.
When managing multiple domains, it is essential to organise reports in a way that allows for easy identification of issues. A hosted or managed setup, such as the one provided by DMARC Engine, can help simplify this process by providing a centralised dashboard for monitoring and analysing reports. For instance, our platform allows users to filter reports by domain, date range, and authentication result, making it easier to pinpoint problems.
One common challenge organisations face is dealing with a large volume of reports. To mitigate this, it is crucial to implement a robust reporting system that can handle the influx of data. We recommend setting up a dedicated email address for receiving aggregate reports and using a parsing tool to extract relevant information. This can be done using a simple script, such as the one below, which extracts the report metadata and authentication results:
import email
import json
def parse_rua_report(report):
# Extract report metadata
metadata = {
'report_id': report['report-id'],
'date_range': report['date-range'],
'domain': report['domain']
}
# Extract authentication results
auth_results = []
for record in report['record']:
result = {
'source_ip': record['source-ip'],
'spf': record['spf']['result'],
'dkim': record['dkim']['result'],
'dmarc': record['dmarc']['result']
}
auth_results.append(result)
return metadata, auth_results
# Example usage
with open('report.txt', 'r') as f:
report = email.message_from_file(f)
metadata, auth_results = parse_rua_report(json.loads(report.get_payload()))
print(metadata)
print(auth_results)This script can be modified to suit the specific needs of the organisation and integrated with existing monitoring tools.
Another critical aspect of interpreting aggregate reports is identifying and addressing authentication issues. A common problem we see is SPF alignment issues, where the SPF record is not correctly configured, leading to authentication failures. For example, consider the following SPF record snippet:
v=spf1 include:_spf.example.com -allIn this example, the SPF record includes the _spf.example.com subdomain, but the -all directive at the end indicates that all other IP addresses are rejected. If the organisation has multiple mail servers with different IP addresses, this configuration can lead to authentication failures. To resolve this issue, we recommend using a more permissive SPF record, such as:
v=spf1 include:_spf.example.com include:_spf2.example.com ~allThis configuration allows for a more flexible SPF setup, reducing the likelihood of authentication issues.
DKIM key management is another area where organisations often struggle. With multiple domains and mail servers, managing DKIM keys can become complex. We recommend implementing a centralised DKIM key management system, such as the one provided by DMARC Engine, which allows for easy rotation and management of DKIM keys. For instance, our platform provides a simple interface for generating and deploying new DKIM keys, as well as monitoring key usage and expiration dates.
When analysing aggregate reports, it is essential to consider the colour of the report, which indicates the authentication result. A red report indicates a failure, while a green report indicates a pass. However, it is crucial to note that a green report does not necessarily mean that the email was delivered successfully. Other factors, such as content filtering and user engagement, can still affect delivery. To optimise email deliverability, organisations should focus on improving authentication results, as well as monitoring and addressing other factors that may impact delivery.
In addition to authentication issues, aggregate reports can also provide insights into email sending patterns and potential security threats. For example, a sudden increase in email volume from a specific IP address may indicate a spamming attempt. We recommend monitoring report data for suspicious activity and implementing additional security measures, such as IP blocking or rate limiting, to prevent abuse.
In conclusion to this section, interpreting aggregate reports is a critical task for large-scale organisations, requiring a deep understanding of email authentication and reporting. By implementing a robust reporting system, addressing authentication issues, and monitoring report data, organisations can improve email deliverability and prevent security threats. As a hosted or managed setup, such as DMARC Engine, can simplify this process, we recommend considering such solutions to optimise email authentication and deliverability.
Optimising Email Deliverability through Effective Authentication
To optimise email deliverability, organisations with complex structures must centre their efforts on effective authentication, which involves aligning domain configuration with the actual email sending patterns. This is crucial as incorrect or incomplete authentication can lead to emails being flagged as spam or rejected outright. For instance, a company like BBC, with various subsidiaries and departments, needs to ensure that each domain and subdomain has the correct SPF, DKIM, and DMARC records in place.
A key aspect of effective authentication is managing SPF records. SPF records list the IP addresses that are authorised to send emails on behalf of a domain. In a complex organisational structure, this can become cumbersome due to the number of senders and IP addresses involved. For example, a company might use multiple marketing platforms, each with its own set of IP addresses, and these need to be included in the SPF record.
TXT "v=spf1 include:_spf.example.com include:mailgun.org -all" In this example, example.com is including the SPF records of _spf.example.com and mailgun.org, allowing emails sent from these services to be authenticated. However, it's essential to keep the SPF record concise and not exceed the 255-character limit or the 10 lookup limit, as this can lead to SPF permerror, causing delivery issues.
DKIM key management is another critical component. DKIM involves encrypting an email's header and content with a private key, and the receiving server verifies this using a public key published in the domain's DNS. For complex organisations, managing multiple DKIM keys across different domains and senders can be challenging. It's recommended to use a centralised DKIM key management system, especially in hosted or managed setups, to ensure that keys are properly rotated and aligned with the organisational structure.
DMARC, which builds upon SPF and DKIM, provides a mechanism for the recipient to report back to the sender about the authentication results. This feedback is invaluable for identifying and fixing authentication issues. However, interpreting these reports, known as aggregate reports (RUA), can be daunting, especially for large organisations with numerous senders and domains. A hosted or managed DMARC setup can significantly simplify this process by providing a centralised dashboard to monitor and analyse these reports, helping to pinpoint issues such as unauthenticated emails or alignment problems.
To further optimise deliverability, organisations should also consider implementing MTA-STS (Mail Transfer Agent Strict Transport Security), which forces a secure connection (TLS) between mail servers, protecting against eavesdropping and tampering. Configuring MTA-STS involves publishing a policy in the domain's DNS that specifies the expected behaviour for mail servers.
TXT "_mta-sts.example.com. v=STSv1; id=1"And then hosting a policy file on a web server that mail servers can access to verify the policy. This step is crucial for ensuring that emails are transmitted securely and can help in preventing man-in-the-middle attacks.
In real-world scenarios, the complexity of organisational structures often leads to overlooked subdomains or newly acquired domains lacking proper authentication. Regular audits and automated monitoring can help mitigate these risks. For example, using DNS scanning tools to periodically check for missing or misconfigured SPF, DKIM, and DMARC records across all domains and subdomains. Also, implementing a centralised email authentication management system can streamline the process of keeping records up to date and aligned with the organisation's email sending practices.
Effective authentication also involves considering the colour of the organisation's email sending reputation. A good reputation is built over time by consistently sending authenticated and engaged-with emails. However, this reputation can be tarnished by a single misstep, such as a spam outbreak from an unauthenticated source. Therefore, it's crucial to monitor email feedback loops and adjust sending practices accordingly to maintain a positive reputation.
In conclusion to the optimisation process, organisations must continually assess and refine their email authentication strategies. This involves staying up to date with the latest standards and best practices, such as BIMI (Brand Indicators for Message Identification), which allows brands to specify a logo to be displayed next to authenticated emails in supporting email clients. By prioritising effective authentication and continually optimising their email deliverability strategies, organisations can significantly reduce the risk of their emails being marked as spam, thereby improving communication with their customers and stakeholders.
Common Pitfalls and Best Practices for Email Administrators
When managing email authentication for domains with complex organisational structures, administrators often encounter a multitude of challenges that can impact email deliverability. One common pitfall is the mismanagement of SPF records, particularly when dealing with acquired domains or subsidiaries. For instance, if a company acquires a new domain, it is essential to update the SPF record to include the new domain's mail servers. Failure to do so can lead to email delivery issues, as seen in the following example:
v=spf1 include:_spf.example.com -allIn this example, the SPF record includes the _spf.example.com mechanism, which may not be valid for the newly acquired domain. To avoid this issue, it is recommended to use a hosted or managed setup, such as DMARC Engine, which can help optimise and manage SPF records across multiple domains.
Another common mistake is the incorrect configuration of DKIM keys. DKIM keys should be rotated regularly to maintain security, but this can be a complex process, especially in large organisations. A best practice is to use a centralised key management system, which can help automate the rotation process and ensure that all mail servers are using the correct keys. For example:
default._domainkey.example.com. IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCqGKukO1De7zhZj6+H0qtjTkVxwTCpvKe4eCZ0FPqri0cb2JZfXJ/DgYSF6vUpwmJG8wVQZKjeGcjDOL5UlsuusFncCzWBQ7RKNUSesmQRMSGkVb1/3j+skZ6UtW+5u09lHNsj6tQ51s1SPrCBkedbNf0Tp0GbMJDyR4e9T04ZZwIDAQAB"In this example, the DKIM key is stored in a TXT record, which can be easily updated and rotated using a centralised key management system.
MTA-STS is another area where administrators often make mistakes. MTA-STS requires a valid TLS certificate to be configured on the mail server, which can be a challenge in complex organisational structures. A best practice is to use a wildcard TLS certificate, which can cover multiple subdomains and make it easier to manage. For example:
smtp.example.com. IN TLSA 0 0 1 d2a85f686d47d6e6e714b6cc8d2a85f686d47d6e6In this example, the TLSA record specifies the TLS certificate for the smtp.example.com domain, which can be easily updated and managed using a hosted or managed setup.
When interpreting aggregate reports, administrators should be aware of the potential for false positives and false negatives. False positives can occur when a legitimate email is flagged as spam, while false negatives can occur when a spam email is not flagged. To avoid this issue, it is recommended to use a hosted or managed setup, which can help filter out false positives and false negatives. For example, DMARC Engine provides a detailed analysis of aggregate reports, which can help administrators identify and fix email deliverability issues.
In terms of optimising email deliverability, administrators should focus on implementing a robust email authentication strategy. This includes configuring DMARC, SPF, and DKIM correctly, as well as monitoring aggregate reports and making adjustments as needed. A best practice is to use a centralised management system, which can help automate and optimise email authentication across multiple domains. By following these best practices and avoiding common pitfalls, administrators can help ensure that their organisation's emails are delivered successfully and that their email authentication strategy is effective.