Date: Fri, 29 Aug 1997 23:43:15 +1000 (EST) From: Andrew Reilly <reilly@zeta.org.au> To: freebsd-questions@freebsd.org Subject: Curly sendmail config problem Message-ID: <199708291343.XAA23204@gurney.reilly.home>
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Hello, I have recently installed the "TkRat" MUA on my FreeBSD 2.2.2 system, and have recently discovered that all was not as fantastic as I first thought. The nub of the problem: my From: address is not being re-written correctly, and I can't find the place to fix it properly. I believe that the problem has only manifested itself with the installation of tkrat because tkrat is the first MUA I have installed that generates a "From:" header field, and I can't find a way to turn that off. I think that Tkrat is also the only MUA I have that connects directly to the localhost SMTP socket to deliver mail, rather than just running sendmail -t. I don't want a From: header, because I want sendmail to insert one for me. I want sendmail to do it for me because I want it to look my user name "andrew" up in /etc/userdb.db, and translate it to "reilly@zeta.org.au" which is the mail address at my ISP. Along with a mail address, my ISP provides me with a dynamically allocated IP address which has a real name that is something like dialup73.syd1.zeta.org.au, and different every time I connect, and so consequentally not useful as a hostname. I have therefore assigned my hostname (gurney.reilly.home, for want of something better) to one of the 10.0.0.x addresses, and aliased that onto my lo0 (localhost) network interface. To make things work without resolv.conf files and so on, this is all reflected in name server entries set up on my local name daemon. Now to stop spam, my ISP (Hi Nick!) has tweaked his sendmail host to deny connections to any host that lies about its domain name in the envelope, so I have to make my sendmail lie about it's bogus domain name so that it looks truthful. (I think that's the story.) Anyway, for a while things have been peachy after telling sendmail to masquerade as zeta.org.au, and to also masquerade-envelope. What is happening at the moment is that tkrat is filling out a From: field with a fully qualified (but deliberately bogus) domain name andrew@gurney.reilly.home, and sendmail is dutifully translating that to andrew@zeta.org.au, which is unfortunately the address of another user on zeta.org.au. That is, in this situation sendmail is not performing the user database lookup. I can think of two "correct" answers to this problem, and one lame one (that I'm using to get this message out): I just don't know how to implement either of the correct answers. The lame one is to tell tkrat to use the correct (external) From: address. This is lame because it is a lie in my own domain, that tkrat compensates for by generating a Sender: field. It is also lame because if I ever decided to reply to my own messages, they would have to be routed to my ISP, rather than be delivered locally. The "simplest" correct answer is to stop tkrat from generating a From: header. None of my other mailers (mail, elm, mutt) seem to do that, and the From: address ends up right. I spent this evening poring over the tkrat documentation and sources, but was unable to figure out how to do that: I don't really understand tcl syntax, for starters. The "most" correct answer is to make sendmail do the userdb lookup on the supplied From: address (after figuring out that it is a local user address despite being fully qualified). Unfortunately, sendmail seems to use extra magic to do userdb lookups, rather than exposing the mechanism through the .cf file (where there are plenty of other data base lookups), so I don't know how to get this to happen. I've thought of setting up a duplicate access to the userdb map: Kuserdb btree /etc/userdb and then adding some sender address re-writing rules to use this, but I thought that before burning more hours on that effort I would ask the collected wisdom of the FreeBSD community, the author of tkrat and my ISP. I have to say that despite years of experience as a part-time Unix box admin, it's actually much HARDER to get a system set up properly in a dial-up environment with only one real user than it was to maintain a distributed group of 20 users in a fully-connected, university environment. Sigh. -- Andrew "The steady state of disks is full." -- Ken Thompson
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