Summary
The 10-DNS lookup limit for SPF records is a common challenge for email senders, particularly when using webmail services or multiple third-party sending platforms. Netfirms webmail, for instance, has provided an SPF record that surprisingly consumes all 10 allowed lookups, leaving no room for additional services like SMTP.com. This scenario forces organizations to seek SPF hosting or flattening solutions to ensure proper email authentication and deliverability. The core issue often lies with hosting providers or email services that include excessively complex or bloated SPF records, making it difficult for users to comply with the standard SPF limitations and integrate other necessary sending services.
Key findings
- Bloated SPF records: Certain hosting providers, like Netfirms (owned by Newfold), are known for providing SPF records that are excessively bloated, often consuming all 10 permitted DNS lookups.
- Shared infrastructure: The same bloated SPF includes might be used across multiple hosting brands, such as Hostgator, A2, and Fatcow.
- Multi-provider challenge: When an organization uses its webmail service (e.g., Netfirms) alongside a third-party email service provider (e.g., SMTP.com), it quickly runs into the SPF DNS lookup limit.
- Provider-dependent solutions: A client becomes reliant on SPF hosting or flattening solutions when their primary hosting company consumes all available SPF lookups.
Key considerations
- SPF flattening: Implementing SPF flattening can resolve the 'too many DNS lookups' issue by replacing nested includes with direct IP addresses or a more condensed record.
- Subdomain strategy: Using subdomains for different email sending services (e.g., marketing, transactional) can help manage SPF records separately and avoid hitting the lookup limit on the main domain.
- Hosting provider choice: The quality of a hosting provider's SPF management might indicate the overall quality of their email service. If email deliverability is critical, consider switching to a provider with better SPF practices or using dedicated email service providers.
- Troubleshooting tools: Utilize SPF record checkers to diagnose lookup issues and identify specific problem areas within your record.
What email marketers say
Email marketers often face significant headaches when their hosting provider's default SPF record consumes the entire 10-DNS lookup quota. This problem is particularly acute for businesses that rely on multiple email sending services. Many marketers express frustration with the lack of flexibility and support from such providers, who may offer inadequate solutions or, worse, dismiss the issue entirely. The consensus among marketers is that such limitations severely hinder their ability to properly authenticate all legitimate sending sources, leading to deliverability challenges and a potential impact on email campaigns.
Key opinions
- Frustration with providers: Marketers frequently find it astonishing that some hosting companies provide SPF records that use up all 10 allowed lookups, leaving no room for other platforms.
- Bloated includes: There's a shared experience among marketers regarding providers (like Newfold-owned entities) that use notoriously bloated include mechanisms in their SPF records.
- Dependence on solutions: This issue makes clients dependent on external SPF hosting or flattening services.
- Poor support: Some support teams fail to provide adequate answers or solutions for navigating these SPF lookup limitations.
Key considerations
- Subdomain adoption: Marketers should consider using subdomains for different email sending services to manage SPF records more effectively and avoid lookup conflicts.
- Provider communication: It's advisable to complain to hosting providers about excessive SPF record usage and advocate for better practices.
- Service quality: A hosting provider with a problematic SPF record might indicate broader issues with their email service. Marketers should consider switching providers if email is critical to their operations, as discussed on Spiceworks Community.
- SPF flattening as a solution: When issues persist, an SPF hosting or flattening solution becomes a necessary step to manage complexity and ensure deliverability.
Marketer view
Email marketer from Email Geeks notes that Netfirms is owned by Newfold and their SPF includes are often bloated, which explains why the record consumes so many lookups.
Marketer view
Email marketer from DuoCircle suggests that SPF record flattening can optimize records and resolve the issue of too many DNS lookups by consolidating entries.
What the experts say
Email experts weigh in on the SPF lookup limit issue, particularly with providers like Netfirms, by emphasizing strategic domain management and robust authentication solutions. They often point out that a bloated SPF record signals broader issues with a mail service provider. Experts advocate for the judicious use of subdomains to segregate different email streams and reduce the burden on the main domain's SPF record. When direct control over the SPF record remains challenging, professional SPF hosting or flattening services are frequently recommended as a pragmatic workaround to maintain deliverability and compliance without exceeding DNS lookup limits.
Key opinions
- Hosted SPF solutions: Several companies offer Hosted SPF services that can help manage and condense SPF records, making them a viable option for overcoming lookup limits.
- Apex domain consideration: If the apex domain isn't used in the return path for other mail providers, SPF lookup issues might not arise from those external services.
- Provider reliability: A hosting provider's poor SPF management often suggests that their overall mail service might be subpar, prompting a recommendation to find a more reliable provider if email is critical.
- Strategic domain use: The best practice involves separating sending concerns by using distinct subdomains for marketing, transactional, and corporate mail.
Key considerations
- Simplifying records: One approach is to manually modify the SPF record, removing unnecessary include mechanisms (e.g., Google entries) if those services are not actively used by the sender.
- Complexity of change: Breaking out into subdomains can be a complex process akin to 'turning a battleship' due to multiple stakeholders and the need for a solid, slow-paced plan.
- Interim solutions: While transitioning, consider obscuring large lists of senders in public DNS to avoid the 10-DNS lookup limit and centralize SPF record management.
- Deliverability impact: Ignoring SPF issues can lead to emails landing in the spam folder, a critical deliverability problem as highlighted by GoDMARC.
Expert view
Email expert from Email Geeks suggests that hosted SPF services are available from various companies and should be considered to manage lookup limits.
Expert view
Email expert from Spamresource advises that complex SPF records can lead to deliverability issues and should be simplified to ensure proper email flow.
What the documentation says
Technical documentation and research consistently highlight the SPF 10-DNS lookup limit as a critical constraint for email authentication. These sources emphasize that complex SPF records, particularly those with numerous 'include' mechanisms or chained lookups, are prone to exceeding this limit, resulting in 'PermError' failures. Solutions proposed in documentation often revolve around SPF flattening, careful management of domain entries, and the strategic use of subdomains to compartmentalize email sending sources. The underlying principle is to ensure that the SPF record remains concise and efficient to prevent authentication issues and maintain email deliverability.
Key findings
- Lookup limit: SPF records are limited to 10 DNS lookups to prevent denial-of-service attacks, a fundamental constraint that must be managed.
- PermError consequence: Exceeding the 10-lookup limit results in an SPF PermError, which indicates an authentication failure and can lead to emails being rejected or sent to spam.
- Causes of excess lookups: Common causes include multiple include mechanisms, a and mx mechanisms, and nested SPF records from third-party services.
- TXT record usage: SPF records are stored as TXT records in DNS, which are text-based data accessed when needed for authentication.
Key considerations
- SPF flattening: One primary method to fix the PermError is SPF record flattening, which converts all domains in include mechanisms into IP addresses, reducing lookups.
- IP addresses over domains: To reduce DNS lookups, it's best to use IP addresses or CIDR ranges directly in the SPF record instead of including domain names that require further lookups.
- Subdomain delegation: Delegating SPF records to subdomains can effectively manage multiple sending services without impacting the root domain's lookup count.
- Regular audits: Regularly checking and optimizing your SPF record is crucial to ensure it stays within the lookup limits and adapts to changes in your email sending infrastructure.
Technical article
Documentation from DuoCircle states that SPF record flattening is a technique that replaces all nested include mechanisms to optimize SPF records and fix the 'too many DNS lookups' error.
Technical article
Documentation from GoDMARC clarifies that to resolve an SPF PermError, you should simplify the SPF record by reducing the number of DNS lookups, potentially by using IP addresses instead of domain names.
Related resources
7 resources
Related pages
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