seiwald@rtech.UUCP (02/03/87)
REROUTING Rerouting explicit UUCP paths is wrong, and should be abolished. As the UUCP world grows and breaks into domains, complete routing will not be done by the sender's host, but rather by the gateways up and down the domain tree. Thus, most explicit paths will be router generated, just one or two hops to get the letter to the gateway more qualified to resolve the address. The remaining explicit paths will be either return paths for failed deliveries or paths hand made by enlightened users. None of these are candidates for optimization. Smail does not forcibly reroute by default; the installer can turn it on. The blame for fouling a decent path either goes to the person who enabled rerouting or to smail for carrying it out. This closely follows the "guns don't kill, people do" argument, so we can save our breath on that discussion. DUPLICATE HOSTNAMES The problem of duplicate hostnames confusing pathalias into making use of nonexistant connections is a common one, but should slowly improve. With domains, each host need only know about its neighbors in the domain tree. For links between hosts that are far apart in the tree the only constraint is the basic UUCP one: you can't talk to two different host with the same name. For addressing purposes, only the full domain name need be unique. FROMMING The UUCP transport mechanism, smail or anything else, should not touch the From: line. It should only prepend host! to the path on the From_ line. Unfortunately, the standard sendmail config file prepends host! to all sender addresses, including the from argument (-ffrom) and the address on the From: line. The config file distributed with smail leaves the sender addresses alone, and relies on smail to meddle with the From_ line. The From: line should be the domain style address of the sender, but many mail front ends still expect it to be a usable path. SENDMAIL CONFIG Working on sendmail config files takes patience and practice. (Did you know the mailer specific rulesets get called twice for each address?). It is true that you can write a sendmail config file to handle almost any mail configuration; you can also write a C program. It is up to the individual which is easier. The rules to handle route addresses in the sendmail config file distributed with smail were broken the last time I checked. Part of the problem is that they assume smail can parse the route addrs, and smail cannot. For UUCP it is not too important, since the path syntax should suffice. A rerouting mailer which chews up UUCP paths is likely to do the same on route addrs. ETC Smail came about because the interface between sendmail and uux didn't quite line up, particularly with domains and automatic routing in the UUCP world, and something was needed to fill the gap. Originally a 15 line shell script, it has grown somewhat, subsuming enough of sendmail as it grew so that it can now survive without it for small, UUCP only sites. The latest version of smail is 2.1. Its caretaker is Larry Auton, lda@clyde.att.com. Contact him for info on how to get it. Christopher chris@cbosgd.att.com --