On Sun, Dec 29, 2013 at 07:53:53PM -0800, Joe Zeff wrote: > I have a friend who's email service sporadically bounces my email. > Why? Because I own my own domain, I use my hosting company's email > servers instead of my ISP's and a small number of their customers > are spammers. Whenever their spam gets above a certain threshold, > her ISP blocks any email access from those servers, and cuts us off. It's called a shared server, and is one of the greatest complaints I get from my clients. Essentially, ISPs in the past have often used the same server to deliver E-Mail for multiple--often hundreds--of hosted clients. As you've discovered, one bad neighbor will cause the shared server IP to be blocked. Given the current state of SMTP protocol and the ability to forge anything except the IP, there's nothing to do about this--there is no better way to identify offenders. The solution is to get a private IP from your ISP if they're hosting your mail server. It usually costs a few dollars to do so, but guarantees that your IP isn't tainted by others on the same server. (There are some RBLs that reject by IP blocks, but most have fallen by the wayside over time.) > This is why I dislike blacklists: they're just about guaranteed to > produce at least 99% false positives because they're just an > exercise in throwing the baby out with the bath water. Most RBLs have options to request delisting, and even without that will usually delist after a few hours unless there's a repeat report. Most ISPs have an interest in clearing their servers from RBLs, and if notified that one or more of their IP addresses are blocked will take steps to identify and clear up shared host problems. Yes, there are some RBLs that are "bad eggs". If they regularly provide bad rejections, mailhosts stop using them. The worst problem is from the major ISPs themselves--e.g., Yahoo, and most particularly Hotmail. They maintain their own internal blacklists, don't give tools for identification, and have horrible removal request/response policies. Cheers, -- Dave Ihnat dihnat@xxxxxxxxxx -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
