[lug] SMTP delivery: No route to host

[Michael Shuler]

Nate Duehr wrote:
> What we really need is new groundbreaking work on server to server
> authentication and identification and then further work in the end-user
> to end-user realm.

Yes!  I work with customers every day, some of whom are very 
non-technical, that do not know that their servers are being used to 
relay thousands of mails a day.  Maybe their bandwidth jumped.  For 
some, they just thought, for instance, that opening a relay domain to 
aol.com was how their road warriors could send mail through the server - 
it worked, but also for every other aol user.  Or someone that has no 
idea that old formmail scripts are being used to relay.  Or someone 
simply never upgraded any software on that old RH6.1 box because it has 
been working fine for years, and their server has been used to send 
millions of mails, and they never thought twice, because their website 
was working great.

They don't know any different until they get blacklisted and mails start 
to bounce.  Then I get calls from everyone else on the network, some of 
them very dilligent and security conscious, that also got blacklisted 
because of the common practice of the bl folks to indiscriminately list 
the entire /24 or /16.  The bl maintainers are, generally, quite 
difficult to work with, with regards to removing IPs or subnets.  It 
usually takes begging to even get a reply.

An advanced method of mailserver identification and auth would be a 
great step in the right direction.

> Why aren't the largest ISP's lobbying for stricter laws?  Because
> they're using spam filters as MARKETING FODDER.  "Use
> AOL/Earthlink/Idiots-R-Us!  We'll protect you from the big bad
> Internet!"

Filtering and blocking is fine as a temporary bandaid.  The problem is 
that both methods are still processing the mail, using precious cycles 
and bandwidth.

I cannot really think of how to approach a modern mailserver handshake 
that could be utilized to this end, but Nate has peaked my interest.

Michael