On 28 Mar 2015, at 3:30, @lbutlr wrote:
I am getting some "Host or domain name not found. Name service error for name=gmail.com type=MX: Host not found, try again” (also for spamhaus.org, surbl.org, dnsbl.sorbns.net and others). I figure the rbi errors are just load issues or timeout issues, but the gmail failure concerns me (especially since when I released that message from the mailq, I got the same error.
I don't recall the exact mechanics of the failure off the top of my head, but I recognize this as an intermittent symptom of using a BINDv9 resolver on a host that supports IPv6 but lacks useful IPv6 connectivity. It occurs intermittently for zones that have a mix of IPv4 and IPv6 resolvers. To fix it, you'll want to add "-4" to the flags for named.
From the command line, can I duplicate how postfix does the DNS query, because I am not seeing any DNS issues when I check via dig?
I'm not sure if it precisely replicates Postfix's query options, but invoking dig repeatedly with "+fail +retry=0" should give you the best change of reproducing intermittent/transient errors visibly. Adding "+trace" will show you details about how you reach wherever the failure is.
