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. -- john r pierce N 37, W 122 santa cruz ca mid-left coast