On 3/26/2014 10:46 AM, Viktor Dukhovni wrote: > On Wed, Mar 26, 2014 at 08:57:54AM -0500, deoren wrote: > >> On March 21st I noticed these entries in my mail log and I'm not able to >> pinpoint the source of the trouble: >> >> warning: x.x.x.x.b.barracudacentral.org: RBL lookup error: Host or domain >> name not found. Name service error for name=x.x.x.x.b.barracudacentral.org >> type=A: Host not found, try again > > Your nameserver logs from that time may shed more light on the reason, > but RBLs are sometimes unavailable due to DDoS, and routing problems can > happen due to bad BGP data, ... that was then and this is now. The > fact that it works now just means that the transient problem is gone. > >> Is there anything obvious I can check? > > log entries from your recursive resolver on whichever machine it > resides on (ideally local to the MTA host).
Note these are common with BRBL. I got a few the very day I added it to my Postfix config years ago. I show the following recent resolution errors for BRBL, the last three trimmed to save space: Mar 25 15:25:31 greer postfix/smtpd[12892]: warning: 58.0.53.80.b.barracudacentral.org: RBL lookup error: Host or domain name not found. Name service error for name=58.0.53.80.b.barracudacentral.org type=A: Host not found, try again Mar 21 08:05:25 greer postfix/smtpd[28711]: warning: 70.233.116.74.b.barracudacentral.org: RBL lookup error: Host or domain Mar 21 11:07:38 greer postfix/smtpd[29257]: warning: 70.233.116.74.b.barracudacentral.org: RBL lookup error: Host or domain Mar 6 05:19:00 greer postfix/smtpd[26724]: warning: 173.197.89.23.b.barracudacentral.org: RBL lookup error: Host or domain I use powerdns recursor locally on my MX. It is designed for, targeted at, extremely high volume query loads, e.g. ISP environments, thus logging such failures would be useless due to the sheer volume. Think web pages containing multiple broken/dead links, then multiply times millions of page loads per day. Cheers, Stan
