Firstly my apologies in advance if "Site & Server Administration" is not the best forum for this topic - I wasn't able to find one specifically for email issues. On to the question. I have a client whose website I host who is having trouble sending email from a mailbox I host. Email sent through the built in webmail doesn't get received, email sent through the server's SMTP server doesn't get received, and email from that address sent through his ISP's SMTP server doesn't get received. There are no error messages - the email just doesn't reach its destination. Other mailboxes on that server work fine, as does sending messages through his ISPs SMTP server from other addresses. The only remaining cause I can think of is that his address and/or domain have found their way onto a spam blacklist (he only sends about 1-2 emails a day, but I guess it could happen). Does anyone know of a facility where one can search to find out if an email address or domain name has been blacklisted by common spam filters?
If you can get the IP address that the mail is being sent from, you can check it in one of the IP blacklists. Here are a couple: http://www.spamhaus.org/ http://dsbl.org/listing You shouldn't really worry about the email address or domain name. I haven't heard of any widely used blacklist for these and even if it did exist, it wouldn't really be effective in stopping spam.
True, but they aren't very effective. It's hard to forge (spoof) IP addresses, but changing your domain is not a problem at all. Plus, it also isn't fair to use or rely on domain blacklists as someone with malicious intent can easily get a legit domain banned. Verification schemes, such as SPF and DKIM, go to some length to fix these problems, but they'll prevail for a while.