nanog mailing list archives
RE: ISP port blocking practice
From: "Paul Stewart" <pstewart () nexicomgroup net>
Date: Fri, 3 Sep 2010 18:22:33 -0400
It's extremely effective for us (not a large provider by any means). We block outbound 25 on all dynamic IP customers - to date it's never been a problem for our customers. Customer's who have static assignments are not blocked by default. Paul -----Original Message----- From: John R. Levine [mailto:johnl () iecc com] Sent: Friday, September 03, 2010 3:20 PM To: Owen DeLong Cc: nanog () nanog org Subject: Re: ISP port blocking practice
It's been extremely effective in blocking spam sent by spambots on large ISPs. It's not a magic anti-spam bullet. (If you know one, please let us know.)That simply hasn't been my experience. I still get lots of spam from
booted hosts in large provider networks, and yes, that includes many that block 25. As near as I can tell, 25 blocking is not affecting spammers at all, just legitimate users. I know people at large ISPs with actual data. Port 25 blocking is quite effective. R's, John
Current thread:
- Re: ISP port blocking practice, (continued)
- Re: ISP port blocking practice Owen DeLong (Sep 03)
- Re: ISP port blocking practice Curtis Maurand (Sep 03)
- Re: ISP port blocking practice Dobbins, Roland (Sep 03)
- Re: ISP port blocking practice Kevin Oberman (Sep 04)
- Re: ISP port blocking practice Owen DeLong (Sep 03)
- Re: ISP port blocking practice Butch Evans (Sep 03)
- Re: ISP port blocking practice Owen DeLong (Sep 03)
- Re: ISP port blocking practice John Levine (Sep 03)
- Re: ISP port blocking practice Owen DeLong (Sep 03)
- Re: ISP port blocking practice John R. Levine (Sep 03)
- RE: ISP port blocking practice Paul Stewart (Sep 03)
- Re: ISP port blocking practice Doug Barton (Sep 03)
- Re: ISP port blocking practice Franck Martin (Sep 03)
- Re: ISP port blocking practice Owen DeLong (Sep 03)
- Re: ISP port blocking practice John R. Levine (Sep 03)
- Re: ISP port blocking practice Robert E. Seastrom (Sep 08)
- RE: ISP port blocking practice Brian Johnson (Sep 12)
- Re: ISP port blocking practice Patrick W. Gilmore (Sep 03)
- Re: ISP port blocking practice Ricky Beam (Sep 03)
- Message not available
- Re: ISP port blocking practice Patrick W. Gilmore (Sep 03)
- Re: ISP port blocking practice Claudio Lapidus (Sep 05)