Problem with large UDP DNS packets through PA DNS Proxy

Showing results for 
Show  only  | Search instead for 
Did you mean: 

Problem with large UDP DNS packets through PA DNS Proxy

L0 Member

We've been using the PA DNS Proxy for quite some time, until recently we noticed that, for some hosts, we could retrieve an A record but not an MX record (the proxy is feeding our mail servers). Eventually we found that we could get that MX record by changing forwarders for the mail servers directly to our DNS boxes, rather than through the PA DNS Proxy (which is being fed from our DNS boxes), i.e. bypassing the DNS Proxy altogether. It seems that the MX response for this particular host results in a UDP packet that is 539 bytes long (EDNS0, of course), which is bigger than the 512 bytes normally allowed for UDP DNS packets (yes, it's definitely UDP, not TCP). Has anyone else seen this problem?

Like what you see?

Show your appreciation!

Click Like if a post is helpful to you or if you just want to show your support.

Click Accept as Solution to acknowledge that the answer to your question has been provided.

The button appears next to the replies on topics you’ve started. The member who gave the solution and all future visitors to this topic will appreciate it!

These simple actions take just seconds of your time, but go a long way in showing appreciation for community members and the LIVEcommunity as a whole!

The LIVEcommunity thanks you for your participation!