Using SUBMIT without bothering the user (was Re: MyDoom, Sorbig - Action

Keith Moore writes:
> no, it wouldn't be nice to be forced to always submit mail from the 
> same location.
> IP addresses are inherently tied to network locations. email addresses 
> are not.
Which reminds me. How is a MUA supposed to find its submit server? RFC 
2476 is silent on that point. "Ask the user" strikes me as a copout.
Can one, for example, do some SRV DNS lookup?

Arnt