rickert@mp.cs.niu.edu (Neil Rickert) (03/14/91)
In article <125491@uunet.UU.NET> kyle@uunet.UU.NET (Kyle Jones) writes: >In article <1991Mar13.003432.14835@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes: > > In article <125390@uunet.UU.NET> kyle@uunet.UU.NET (Kyle Jones) writes: > > > [...] sendmail 5.61. > > > > > > If the recipient mailer is sendmail's builtin SMTP mailer, then > > > the user part of the (mailer, host, user) triple of ruleset 0 > > > will have the sender's domain appended, if the sending mailer has > > > the C flag set and the user part doesn't have a domain spec. > > > This means that the RCPT To: SMTP command is sent out with the > > > _sender's_ domain appended to the recipient, instead of the > > > recipient's own domain. >I no longer have a pristine 5.61 sendmail to look at, but the >problem is still there in sendmail 5.64. Here's the offending >line from src/usersmtp.c: > > smtpmessage("RCPT To:<%s>", m, remotename(to->q_user, m, FALSE, TRUE)); I just checked. You are indeed correct, and this is a SERIOUS bug. My sources contain instead: smtpmessage("RCPT To:<%s>", m, to->q_user); but in checking the RCS archives, I find this correction is part of the IDA mods. > > While I agree you should normally resolve to (tcp,domain,user@domain) > > there are circumstances where it is useful to resolve to just > > (tcp,domain,user) -- in particular this lets you get mail to someone on > > a badly misconfigured host which does not recognize its own domain name. Funny that I happened to mention that yesterday. Today I find that a neighboring machine which uses my host as a relay was recently misconfigured during installation of a new release of SunOS. The result is, it doesn't recognize its own address, and relays it back here. After 17 hops the message is rejected, breaking the mailing loop. I had to resort to the configuration change of removing the domainname before forwarding to the host. Fortunately my sendmail does not suffer from this bug. Incidently, if my 'sendmail' receives a message to 'user@[n1.n2.n3.n4]' it always relays it without a domain name, since many hosts do not recognize their own domain names. I have cross-posted this to comp.bugs.4bsd -- =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= Neil W. Rickert, Computer Science <rickert@cs.niu.edu> Northern Illinois Univ. DeKalb, IL 60115 +1-815-753-6940