I'm encountering a strange DNS / e-mail problem an a mail server running OpenBSD 4.3.
Sometimes, DNS returns completely unexpected results. I get two completely different answers to the same DNS query with the incorrect answers being returned by the DNS server that is being used by the mail server. For example, "whois ruhl.in" shows that the name servers are dns1.name-services.com to dns5.name-services.com. Then, "dig @dns1.name-services.com -t mx ruhl.in" returns: ********************************************************************* ; <<>> DiG 9.4.2 <<>> @dns1.name-services.com -t mx ruhl.in ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3610 ;; flags: qr aa; QUERY: 1, ANSWER: 5, AUTHORITY: 5, ADDITIONAL: 5 ;; QUESTION SECTION: ;ruhl.in. IN MX ;; ANSWER SECTION: ruhl.in. 1800 IN MX 10 ASPMX.L.GOOGLE.COM. ruhl.in. 1800 IN MX 20 ALT1.ASPMX.L.GOOGLE.COM. ruhl.in. 1800 IN MX 30 ALT2.ASPMX.L.GOOGLE.COM. ruhl.in. 1800 IN MX 40 ASPMX2.GOOGLEMAIL.COM. ruhl.in. 1800 IN MX 50 ASPMX3.GOOGLEMAIL.COM. ;; AUTHORITY SECTION: ruhl.in. 3600 IN NS dns1.name-services.com. ruhl.in. 3600 IN NS dns2.name-services.com. ruhl.in. 3600 IN NS dns3.name-services.com. ruhl.in. 3600 IN NS dns4.name-services.com. ruhl.in. 3600 IN NS dns5.name-services.com. ;; ADDITIONAL SECTION: dns1.name-services.com. 3600 IN A 98.124.192.1 dns2.name-services.com. 3600 IN A 69.64.157.18 dns3.name-services.com. 3600 IN A 98.124.193.1 dns4.name-services.com. 3600 IN A 69.64.145.225 dns5.name-services.com. 3600 IN A 70.42.37.7 ********************************************************************* But if I use the name server used by the e-mail server, "dig -t mx ruhl.in", returns: ********************************************************************* ; <<>> DiG 9.4.2 <<>> -t mx ruhl.in ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26226 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;ruhl.in. IN MX ;; ANSWER SECTION: ruhl.in. 471 IN CNAME ghs.google.com. ghs.google.com. 482751 IN CNAME ghs.l.google.com. ;; AUTHORITY SECTION: l.google.com. 60 IN SOA e.l.google.com. dns-admin.google.com. 1380328 900 900 1800 60 ********************************************************************* When I change the /etc/resolv.conf file on the mail server to swap the order of the DNS servers, then dig returns the correct records for a little while until the records expire and then switches to the incorrect one! Meanwhile, the DNS server that had been listed first and is now second begins to return the correct records once those records expire. Has anyone seen this kind of behavior before? Can anyone explain what is happening here? It's driving me up the wall. Eric Johnson
