I sent someone a mail a little while ago and it was returned. The mailer daemon at the remote end said the outgoing SMTP server was listed in spamcop. That had me worried.
Then I realised that the mail was actually sent through the Sri Lanka Telecom mail server rather than mine. I get DSL services from Sri Lanka Telecom. The uplink is supposed to be 128Mbps but you never get even one tenth of that. As a result when having to send mails with attachments, I am forced to use their mail server rather than my own.
Sure enough smtp.slt.lk, which now resolves to 22.214.171.124 is listed on spamcop. What's really shocking is that SLT has been listed 15 times during the past one year. Then again, it's not really suprising.