Some senders are reporting inconsistent, hard-to-pin-down authenticated-related delivery failures when sending to Microsoft domains.
Here's a theory about on thing that might be related: overly short DNS TTL (time-to-live) settings on SPF, DKIM, or CNAME records might be contributing to these problems. Short TTLs can lead to more frequent DNS lookups, which increases the chance of timeouts or resolution delays. If DNS queries fail during authentication checks, Microsoft might reject the message, even if everything is otherwise configured correctly.
Steve Atkins at Word to the Wise recently wrote about why longer TTLs tend to be more reliable and how short TTLs can add risk, especially under load. He also discusses how DNS behavior may interact with Microsoft's stricter authentication enforcement.
If you're troubleshooting Microsoft delivery issues, this is something worth considering.
Some senders are reporting inconsistent, hard-to-pin-down authenticated-related delivery failures when sending to Microsoft domains.
Here's a theory about on thing that might be related: overly short DNS TTL (time-to-live) settings on SPF, DKIM, or CNAME records might be contributing to these problems. Short TTLs can lead to more frequent DNS lookups, which increases the chance of timeouts or resolution delays. If DNS queries fail during authentication checks, Microsoft might reject the message, even if everything is otherwise configured correctly.
Steve Atkins at Word to the Wise recently wrote about why longer TTLs tend to be more reliable and how short TTLs can add risk, especially under load. He also discusses how DNS behavior may interact with Microsoft's stricter authentication enforcement.
If you're troubleshooting Microsoft delivery issues, this is something worth considering.
Read the full post here: Don't Make Your DNS TTLs Too Short
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