nanog mailing list archives
Re: The End-To-End Internet (was Re: Blocking MX query)
From: "Joe St Sauver" <joe () oregon uoregon edu>
Date: Wed, 5 Sep 2012 14:15:07 -0700 (PDT)
Izaac <izaac () setec org> commented: #I suspect your ISP is also stripping <sarcasm> tags. Let's try it out #again: # # You can tell that tcp port 25 filtering is a highly effective spam # mitigation technique because spam levels have declined in direct # proportion to their level of deployment. Today, we barely see any # spam on the internet due to amazing ability of these filters to # prevent bad people from sending bulk email. # #Was that properly marked? Actually, not sure sarcasm tags are appropriate. 1) Port 25 blocks target direct-to-MX spam delivered by bots. 2) The Spamhaus CBL tracks the level of bot spam currently seen, including breaking out statistics by a number of factors. 3) Currently, the US, where port 25 filtering is routinely deployed by most large ISPs, is ranked 158th among countries when you consider botted users on a per capita basis: http://cbl.abuseat.org/countrypercapita.html 4) While that's not perfect (after all, there are still at least 133,811 listings for the US), on a PER-CAPITA basis, it's not bad -- that's just ~0.055% of US Internet users that are infected, relative to some countries where the rate of detected infection (based on spam emission) may be 4 to 5% or more. So yes, actually, port 25 blocks *DO* tend to be effective in reducing bot-delivered email spam. Does this mean that port 25 blocks are the ONLY measure that is required to control spam? No, absolutely not. But it does clearly help. Regards, Joe
Current thread:
- Re: The End-To-End Internet (was Re: Blocking MX query), (continued)
- Re: The End-To-End Internet (was Re: Blocking MX query) Masataka Ohta (Sep 11)
- Re: The End-To-End Internet (was Re: Blocking MX query) valdis . kletnieks (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) Mark Andrews (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) valdis . kletnieks (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) Sean Harlow (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) Owen DeLong (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) Masataka Ohta (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) Mark Andrews (Sep 06)
- Re: The End-To-End Internet (was Re: Blocking MX query) valdis . kletnieks (Sep 07)
- Re: The End-To-End Internet (was Re: Blocking MX query) Rich Kulawiec (Sep 08)