seen in logs here is that eg bounce.linkedin.com have a ipv6 only hostname in there mx, problem there in is that postfix says unknown hostname on ipv4 servers Reproducible: Always
$ dig -t mx bounce.linked.com ; <<>> DiG 9.9.4 <<>> -t mx bounce.linked.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61227 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 3 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;bounce.linked.com. IN MX ;; ANSWER SECTION: bounce.linked.com. 3600 IN MX 0 mail.b-io.co. ;; AUTHORITY SECTION: linked.com. 172800 IN NS ns2.dnslink.com. linked.com. 172800 IN NS ns1.dnslink.com. ;; ADDITIONAL SECTION: ns1.dnslink.com. 30460 IN A 66.135.37.197 ns2.dnslink.com. 30460 IN A 72.51.33.53 ;; Query time: 317 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Tue Nov 19 03:03:44 AZOT 2013 ;; MSG SIZE rcvd: 150 $ dig -t any mail.b-io.co ; <<>> DiG 9.9.4 <<>> -t any mail.b-io.co ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39327 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;mail.b-io.co. IN ANY ;; ANSWER SECTION: mail.b-io.co. 60 IN A 54.235.175.126 ;; AUTHORITY SECTION: b-io.co. 7200 IN NS ns-1712.awsdns-22.co.uk. b-io.co. 7200 IN NS ns-477.awsdns-59.com. b-io.co. 7200 IN NS ns-773.awsdns-32.net. b-io.co. 7200 IN NS ns-1099.awsdns-09.org. ;; ADDITIONAL SECTION: ns-477.awsdns-59.com. 30743 IN A 205.251.193.221 ns-773.awsdns-32.net. 30668 IN A 205.251.195.5 ns-1099.awsdns-09.org. 35925 IN A 205.251.196.75 ns-1712.awsdns-22.co.uk. 33253 IN A 205.251.198.176 ;; Query time: 143 msec ;; SERVER: 192.168.1.1#53(192.168.1.1) ;; WHEN: Tue Nov 19 03:04:02 AZOT 2013 ;; MSG SIZE rcvd: 261 As you can see from above, bounce.linkedin.com resolves to an ipv4 address. To configure postfix to use ipv6 or not, you need to configure the inet_protocols variable in /etc/postfix/main.cf.
linked.com is not linkedin.com
when was ipv6 use flag removed ? building postfix now enables ipv6 support on kernels where its disabled, are we begining to force ipv6 on ? there is no ./configure in tarball, sorry i did not check this before main problem is still that postfix gives warning on ipv6 only hostnames that is used eg in linkedin.com when i created this bug sorry if i typed linked.com on irc, but here i have always writed linkedin.com
Unable to look up MX host for sender address, Name or service not known, mail-c6.linkedin.com was what i see in logs
http://postfix.1071664.n5.nabble.com/warning-Unable-to-look-up-MX-host-td5156.html http://tools.ietf.org/html/draft-martin-smtp-ipv6-to-ipv4-fallback-00 http://tools.ietf.org/html/draft-martin-smtp-target-host-selection-ipv4-ipv6-00 (quote) If Postfix is configured for IPv4 only, then looking up IPv6 addresses is not useful. Just ignore the warning. The combination of IPv4-only clients and IPv6-only servers is a temporary thing. Wietse (/endqoute) but if there is a warning it did anyway
Uhm, so just ignore the warning. Postfix will try the other MXes.
