nanog mailing list archives
Re: Spamhaus...
From: Larry Sheldon <LarrySheldon () cox net>
Date: Sat, 20 Feb 2010 20:29:10 -0600
On 2/20/2010 4:57 PM, James Hess wrote: For the purpose of the following two paragraphs, pretend for the moment that you operate a business selling stuff via an email address Sales () Example Com. For dramatic effect, assume your children will starve if you are not able to sell anything. Further, pretend that you have really annoyed somebody--a competitor, perhaps. Suppose that your competitor has contracted with a real, genuine spammer to send email mmessages advertizing some trash at a rate of tens of thousands per second until the bot-net gets shut down using Sales () Example Com as the Return-Path. Now. Read the two paragraphs.
Spurious DSNs are less harmful than missing DSNs. Spurious DSNs can be discarded easily by the mail server that knows it didn't pass that message. DSNs that were not generated cannot be recovered. Discarding is currently the responsibility of the mail server whose address has been forged. Just like it's the responsibility of a host whose source address was forged in a TCP transaction, to discard the "ACK" packet for a connection that resulted from a spoofed SYN.
Anything about those two 'graphs you would like to reconsider? And by the way, when I was running a network, if I got very many errant SYN's from a particular source, that source would get a static route to a 500 ohm resistor.
The mail server sending DSN for the fake message, or replying to a spoofed SYN is not a spammer in any way, they are actually a victim wasting their own bandwidth responding to a bogus message.
Victim they may be, spammer they are, The definition of "spammer" does not include a "get even with the world" or "do unto others as was done unto you" clauses. -- "Government big enough to supply everything you need is big enough to take everything you have." Remember: The Ark was built by amateurs, the Titanic by professionals. Requiescas in pace o email Ex turpi causa non oritur actio Eppure si rinfresca ICBM Targeting Information: http://tinyurl.com/4sqczs http://tinyurl.com/7tp8ml
Current thread:
- Re: Spamhaus..., (continued)
- Re: Spamhaus... John Levine (Feb 20)
- Re: Spamhaus... Graeme Fowler (Feb 21)
- Re: Spamhaus... Michelle Sullivan (Feb 21)
- Re: Spamhaus... Jon Lewis (Feb 21)
- Re: Spamhaus... Tony Finch (Feb 21)
- Re: Spamhaus... Michelle Sullivan (Feb 21)
- Re: Spamhaus... Jon Lewis (Feb 21)
- Re: DNSBLs other than Spamhaus... John Levine (Feb 21)
- Re: Spamhaus... Larry Sheldon (Feb 21)
- Re: Spamhaus... Matthias Leisi (Feb 21)
- Re: Spamhaus... Larry Sheldon (Feb 20)
- Re: blowback, was Spamhaus... John Levine (Feb 20)