SMTP receiver rejections

Craig Partridge (
Wed, 28 May 86 09:33:00 -0400

> There are no hard rules on this and our implementation chooses to reject
> mail where the only host specified is unknown. UNIX is not so rigorous,
> it will accept mail from (or for) any host whether it exists or not, and
> will then have no way of informing anyone but the mail system maintainer
> that there is a problem. We like the TOPS-20 system better where the
> originator has to resolve the problem.


    I generally agree with the goal but do want to point out that our
experience at CSNET is that, more often than not, the problem is not the
originator's but that of the receiving mail system, which either has
out of date host tables (presumably under domains this problem will become
one of having a defective or ill-informed nameserver) or some configurational
error which causes it to reject the message.

Craig Partridge
CSNET Technical Staff

This archive was generated by hypermail 2.0b3 on Thu Mar 09 2000 - 14:36:33 GMT