I run a shared webhosting company. My ThePlanet server was getting too slow and having hardware problems. I moved to a new colo December 15. Unfortunately, the ip address given to me lies in a netblock which had been used previous for spam. THe spammers were kicked out of the building, however, it still has quite the reputation on SORBS. Move from IP with spotless reputation 126.96.36.199 to 188.8.131.52. (A quick search of whois.sc history will prove the claim I moved.) I've opened a ticket with the colo with instructions to contact SORBS, pay their ransom and learn to vet their clients better. Anyhow, I want to use mail_reverse_dns and mailips to direct mail out of a particular IP, one which is is better repute. SO my question, finally is this, when doing so, do I need to use a different hostname? I know the ip is blacklisted (not my fault! -- I've done nothing wrong!) but is the hostname too? I made the causal mistake of naming the server after my second-born son. So should I also change the mail_reverse_dns and the reverse dns entry to a new hostname, or stick with the old one?