Hi Guys The server has been running great after the extra protection I put in place. SPF is causing me some hassle, and I want to know how to properly respond to such issues. Every now and again, we get domains that send emails from a seperate server to its parent domain. Im sure that this is a configuration problem their end, but I don't know what to say 100% back to my clients as to why some emails are not getting through to them. Sep 26 09:18:29 isc postfix/smtpd[28932]: warning: hostname drydensfairfax.com does not resolve to address 77.89.147.131 Sep 26 09:18:29 isc postfix/smtpd[26785]: warning: hostname drydensfairfax.com does not resolve to address 77.89.147.131 Sep 26 09:18:30 isc postfix/smtpd[28932]: NOQUEUE: reject: RCPT from unknown[77.89.147.131]: 450 4.7.1 Client host rejected: cannot find your hostname, [77.89.147.131]; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<mail1.drydensfairfax.com> Sep 26 09:18:30 isc postfix/smtpd[26785]: NOQUEUE: reject: RCPT from unknown[77.89.147.131]: 450 4.7.1 Client host rejected: cannot find your hostname, [77.89.147.131]; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<mail1.drydensfairfax.com> Please see dig of both dns with different IP addresses. Code: dig 77.89.147.131 ; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> 77.89.147.131 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 45669 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;77.89.147.131. IN A ;; AUTHORITY SECTION: . 10800 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2016092600 1800 900 604800 86400 ;; Query time: 14 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Mon Sep 26 12:03:54 2016 ;; MSG SIZE rcvd: 106 root@isc:~# dig drydensfairfax.com ; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> drydensfairfax.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7555 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4 ;; QUESTION SECTION: ;drydensfairfax.com. IN A ;; ANSWER SECTION: drydensfairfax.com. 2809 IN A 77.89.147.140 ;; AUTHORITY SECTION: drydensfairfax.com. 26808 IN NS dns086.c.register.com. drydensfairfax.com. 26808 IN NS dns036.b.register.com. drydensfairfax.com. 26808 IN NS dns010.d.register.com. drydensfairfax.com. 26808 IN NS dns196.a.register.com. ;; ADDITIONAL SECTION: dns010.d.register.com. 26808 IN A 216.21.236.10 dns036.b.register.com. 26808 IN A 216.21.232.36 dns086.c.register.com. 26808 IN A 216.21.235.86 dns196.a.register.com. 26808 IN A 216.21.231.196 ;; Query time: 0 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Mon Sep 26 12:04:24 2016 ;; MSG SIZE rcvd: 217 root@isc:~# dig mail1.drydensfairfax.com ; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> mail1.drydensfairfax.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45831 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4 ;; QUESTION SECTION: ;mail1.drydensfairfax.com. IN A ;; ANSWER SECTION: mail1.drydensfairfax.com. 14400 IN A 77.89.147.142 ;; AUTHORITY SECTION: drydensfairfax.com. 26540 IN NS dns010.d.register.com. drydensfairfax.com. 26540 IN NS dns036.b.register.com. drydensfairfax.com. 26540 IN NS dns086.c.register.com. drydensfairfax.com. 26540 IN NS dns196.a.register.com. ;; ADDITIONAL SECTION: dns010.d.register.com. 26540 IN A 216.21.236.10 dns036.b.register.com. 26540 IN A 216.21.232.36 dns086.c.register.com. 26540 IN A 216.21.235.86 dns196.a.register.com. 26540 IN A 216.21.231.196 ;; Query time: 142 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Mon Sep 26 12:08:52 2016 ;; MSG SIZE rcvd: 223 Thanks Lee
