The past week’s requests for assistance with blacklist problems have shown an unusual increase in bounceback messages from recipients stating that SORBS has identified spam coming from their specific mail servers. Meanwhile, the ongoing scenario of static IPs being mis-identified as dynamic continues to cause frustration. In fact, nearly 50% of all recent requests have concerned this single blacklist family.

Reverse DNS issues are still interfering with successful de-listing requests: Checks have shown more missing “A” and PTR records…while outbound IP addresses that don’t match up with their domains are also continuing to have an impact.

DID YOU KNOW?

Most ISP hosting companies don’t use public blacklists to protect their customers from spam and virus attacks. However it is common practice for them to build their own private blacklists instead…and as many public ones do, these lists may netblock entire ranges of IP addresses that include known spammers. 

This makes good sense for their customers: All intrusions from that entire range are effectively stopped. It also makes sense for the ISPs themselves: They don’t have to expend time and assets tracking down all the individual spammers. 

Where it doesn’t make sense is for the hundreds — sometimes thousands — of non-spammers who are caught in these netblocks: Individually, each must find a way to commmunicate with these ISPs and let them know that their IP address is not guilty of spamming…and then hope that they will be listed as accepted senders in the future.