In message <[log in to unmask]>, [log in to unmask] writes:
>
> MAIL From:<@host1:user@host2>
>
> Perhaps a more reasonable policy would be to reject source-routed mail
> only if a comparison of host1  and host2 indicates a probable spamming
> attempt through a  relay  (for instance, if  they  do not match to  at
> least a second level  domain.name).   That would be,  to me,  a policy
> based rejection, not a rejection based merely on use of valid syntax.

And I think that even this can be unreasonable. I cite my two cases again:

1) host1 is the corporate firewall, that just happens to also protect my
   machine at home. Specifically:

        MAIL From:<@elgreco.border.com:[log in to unmask]>

2) host1 is an ISP's mail relay host, provided as a service to its less
   technically savvy customers:

        MAIL From:<@mail.uunet.ca:[log in to unmask]>

(Yes, both of these are real examples :-).


Again, to reiterate:

- I have no objection to filtering known spam sources. (I use AOLs
  PreferredMail list of hosts to filter my own incoming e-mail, thanks to
  some perl scripts by YAPH).

- I have no objection to refusing to act as a mail relayer for hosts outside
  your administrative purview (i.e. denying RCPT To:<@host1:user@host2).

- I merely object to rejecting mail based on a source route appearing in the
  MAIL From: command.

--
Harald Koch <[log in to unmask]>