On Wed, Dec 01, 2004 at 12:55:38AM -0400, Trevor Smith wrote: > On December 1, 2004 12:37 am, Ernie McCracken wrote: > > For awhile, I just used sendmail to deliver mail directly. Then I found > > that some of my mail was bouncing because ISPs had deemed my IP address > > was part of a block of DHCP-assigned IP addresses. This was presumably > > done to keep spammers and virus-infected machines from sending mail > > directly from their PC. > > OK, this suggests a few questions to me: > > 1. it appears you are saying that sending directly through my localhost's > sendmail *will* work from different networks. Was that what you found? (I > haven't tested yet.) Yes, sendmail should work no matter what network it's on. However, your ISP or office network may have blocked outbound port 25. I know it's like that where I work. In that case, it won't matter that sendmail works, because none of your mail will get through due to firewall restrictions. > 2. Assuming yes to #1 above, was it sending through sendmail that was causing > people to blacklist you? I don't quite understand the technology involved > well enough to see how this would be a problem. No, it wasn't _me_ in particular that caused it.. at least, I hope not. :-) I think some (many?) ISPs simply blacklist a range of IP addresses that are known to be dynamically assigned. Their rationale being that email coming directly from a machine with an IP address in that range can only be caused by two things: 1. Spammer 2. Somebody's PC that is infected with a virus/trojan I don't know if they still do this, but earthlink.net bounced all my email with a little nastygram that said something to the effect of: "This email came from a dynamically-assigned IP address. Please use your ISP's SMTP server." So I ended up having to use my ISP's SMTP server, or I couldn't get email to my parents because they happen to use earthlink.
