I'm having somehow a strange issue :s I can send to all addresses. I can send and receive to and from all internal addresses. I "can´t receive" from external addresses. Well can´t receive is not accurate, the mail is not delivered to the appropriate Mailbox. Mails are being identified by greylisting. Code: Oct 15 03:08:11 r22146 tumgreyspf: Initial greylisting: REMOTEIP="18.104.22.168" HELO="22.214.171.124-static.reverse.softlayer.com" SENDER="[email protected][email protected] Code: grep "tumgreyspf" /var/log/mail.log | wc -l 30 No mail deferred. Code: qshape incoming active deferred T 5 10 20 40 80 160 320 640 1280 1280+ TOTAL 0 0 0 0 0 0 0 0 0 0 0 Nothing on the mail queue. Code: postqueue -p Mail queue is empty correct mx domain. Code: pico /etc/mailname mx.mydomain.com Code: tumgreyspf: Initial greylisting: REMOTEIP="126.96.36.199" HELO="180-29-207-82.pool.ukrtel.net" SENDER="[email protected] A little more of detail: Looks like the named.conf is ok with the MX record. Code: @ IN SOA ns1.sub.domain.net. webmaster.sub.domain.net. ( 2010101601; serial 2H ; refresh 60M ; retry 1W ; expire 24H ; default_ttl ) @ IN NS ns1.sub.domain.net. @ IN NS sub.domain.net. @ IN MX 5 mail.sub.domain.net. www 7200 IN A 12.34.567.89 pop IN A 12.34.567.89 imap IN A 12.34.567.89 mail IN A 12.34.567.89 smtp IN A 12.34.567.89 ftp IN A 12.34.567.89 However : Code: dig domain.info ; <<>> DiG 9.6-ESV-R1 <<>> domain.info ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60640 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;domain.info. IN A ;; ANSWER SECTION: domain.info. 7200 IN A 12.34.567.89 ;; AUTHORITY SECTION: domain.info. 7200 IN NS ns1.sub.domain.net. domain.info. 7200 IN NS sub.domain.net. ;; ADDITIONAL SECTION: ns1.sub.domain.net. 7200 IN A 12.34.567.89 sub.domain.net. 7200 IN A 12.34.567.89 ;; Query time: 4 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Sun Oct 17 14:45:07 2010 ;; MSG SIZE rcvd: 127 From my understanding shouldn't be an issue there as: - I own a server farm that is allocated to a domain. - Every single server in the farm is associated with a sub-domain. - Every subdomain is a dns server capable for all internal domains. As such the full FQDN of this server in question is sub.domain.com All domains are working as expected to the exception of mail server when related to incoming mail, no issues in sending email. my A and MX records for mail are properly setup for every single domain. A little more of wierdness ;s Internal Nslookup Code: nslookup -type=mx virtualdomain.info Server: 127.0.0.1 Address: 127.0.0.1#53 virtualdomain.info mail exchanger = 5 mail.sub.domain.net. External nslookup Code: nslookup -type=mx virtualdomain.info Server: unknown Address: 192.168.1.1#53 virtualdomain.info mail exchanger = 5 mail.sub.domain.net. Any Clue???