* Joost van der Lugt
On Friday 08 June 2001 12:37, Leah Cunningham wrote:
Joost, do you know if there is a way for the mail server to check if the IP address you are coming from matches the domain given?
Feature is also called allow 'mail based on envelope from':
FEATURE(relay_local_from)
Which is not in the default SuSE sendmail config ( or any newer sendmail config). It is the only way to allow false envelopes in, aside from the promiscuous relay feature, which just allows anything whatsoever at all in:-).
Sendmail does an nslookup on your domain, so it checks no matter what you give as a from address.
The only spoofing you could do (that I can think off) is to spoof your IP address, which is hard to do, to say the least.
Oops, guess I misunderstood the actual question, but as explained by others, it is not a good idear, and I don't know if it's possible. For your own domain(s) you even have to allow an empty from address ... (see the rfc's) so from does not have to equal your actual domain. (so the features I was talking about above regarding the envelopes were regarding relaying of, and allowing and denying of that)
Joost