On 04/12/12 4:35 AM, Peter Peltonen wrote:
$ host 205.234.223.198 198.223.234.205.in-addr.arpa domain name pointer mx4.servershost.net.
$ host mx4.servershost.net mx4.servershost.net has address 66.225.237.241
As you can see the DNS resolves to different IP address than given by the PTR record. Some email systems consider this as an indication of a misconfigured mail server (spam sending attempt) and refuse to relay.
except, thats the receiving server, and it shouldn't be rejecting itself.
$ host -t MX tata-nigeria.com tata-nigeria.com mail is handled by 30 mx4.servershost.net. tata-nigeria.com mail is handled by 10 mx2.servershost.net. tata-nigeria.com mail is handled by 20 mx3.servershost.net. $ host mx4.servershost.net mx4.servershost.net has address 66.225.237.241
the host is probably dualhomed, and that 66 IP matches the reverse...
$ host 66.225.237.241 241.237.225.66.in-addr.arpa domain name pointer mx4.servershost.net.
servershost.net appears to be a US based hosting company, yet their WHOIS data is shrouded, and they dont have any websites at that domain name, further http://rbls.org/servershost.net says they are broken, and have no postmaster or abuse alias as required by the internet RFCs.