Recently I upgraded a bunch of ASG’s to version 8.2. While most of the upgrades went smoothly, I did have an issue with a specific box at one of my clients offices.
We had some reports that incomming e-mails were being rejected. After checking the Mail Manager, these e-mails were being rejected due to numerous RDNS failures. While most of the incomming message sources actually didn’t have a properly configured RDNS, I finally noticed in one case that a specific sender actually did have properly configured Reverse DNS…
Googling this specific issue came up with nothing, however I noticed in the DNS proxy on the ASG box, that since the upgrade numerous errors were going through on a daily basis:
mail named: Last message ‘unexpected RCODE (RE’ repeated 2 times, supressed by syslog-ng on host.name
mail named: lame server resolving ‘X’
These errors were filling the log. I went ahead and logged into WebAdmin and removed the DNS forwarders, hit apply, flushed DNS cache, then re-inserted the DNS forwarders. This resolved the issue.