Xref: utzoo comp.mail.sendmail:96 comp.dcom.lans:1841 Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!rutgers!rochester!uhura.cc.rochester.edu!ur-valhalla!deke From: deke@galaxy.ee.rochester.edu (Dikran Kassabian) Newsgroups: comp.mail.sendmail,comp.dcom.lans Subject: Re: sendmail, the resolver and /etc/hosts Message-ID: <1482@valhalla.ee.rochester.edu> Date: 22 Sep 88 00:36:44 GMT References: <713@ncar.ucar.edu> <1469@valhalla.ee.rochester.edu><1473@valhalla.ee.rochester.edu> <285@hal.UUCP> <729@ncar.ucar.edu> <286@hal.UUCP> <733@ncar.ucar.edu> <287@hal.UUCP> Sender: usenet@valhalla.ee.rochester.edu Reply-To: deke@ee.rochester.edu (Dikran Kassabian) Organization: UR Dept. of Electrical Engg, Rochester NY 14627 Lines: 78 In article <287@hal.UUCP> ane@hal.cwru.edu (Aydin "Bif" Edguer) writes: > Point #1: You should be running the nameserver (at least caching) > on all your machines. > Point #2: Your C library functions should be compiled to use the > nameserver on all your machines. > Point #3: Your networking software (ftp, telnet, sendmail, etc) > should all be compiled using the libraries that use > the nameserver on all your machines. Hmmm. Some of us have binary only distributions to Operating Systems that have a strange mechanism for resolving host names through the "yellow pages" One vendor in particular causes me alot of grief with their lack of under- standing of existance in an Internet environment. But they make great work- stations. On machines where sources are available, I'd make an argument for having two versions of telnet, ftp, finger, rlogin, etc. One that uses nameserver (in /usr/ucb) and the other using /etc/hosts (in /usr/old or something like that). > >All they know is that they can FTP there but they can't mail there, > >and in their eyes it is my fault, since I'm in charge of mail. > [note: this should never happen on your machine since ftp uses > the nameserver too! Unless your running with improperly compiled > programs.] ...Or programs that come with the binary only distribution. Has everyone forgotten what it is like to be without sources? A sysadmin is still expected to make things work. >Here is a possible solution to your problem. >Problem statement: > 1) You want to find problems with incompatibilities > between an /etc/hosts and the nameserver. > 2) You want to find the problems before a user tells you > that their mail is not going through. >Solution statement: > 1) Write a shell program which will > a) go through a file in /etc/hosts format and extract > the fully qualified domain names. > b) take each name found and use nsquery (distributed with > named) to look up each name in the nameserver. > c) Examine the output of nsquery for failure and notify > you. That ought to take about a month and all the cpu I can muster... > d) EXTRA CREDIT: Make it add an entry to your local mod > file for the nameserver. And now I'm a nameserver for the world. > 2) Automate the process of getting the /etc/hosts from offending > machines by using batched ftp (there have been a couple posted > to the net.) Does this assume that every machine has anonymous ftp configured and that the hosts file is ready to be grabbed by anyone? Do I miss your point? >The second possible solution I posted last time - > Hack on sendmail to look up parent domains and forward the mail > to the parent domain (allowing the authoritative server to figure > out the correct address.) This should always work unless the > network goes down (in which case the mail won't be delivered > anyway). meaning turn person@bogushost.do.main into person%bogushost@do.main ? Thats what the users end up doing anyway, but I guess its an okay idea to have sendmail do it. Okay. I'm through making waves for now. Stan Barbor at Baylor says that Bind 4.8 at most recent patch level does what I want.... it asks /etc/hosts if nameserver fails (not to be confused with "if nameserver isn't available") If thats so, we are arguing over nothing. What I'm looking for exists. Can anyone comment? ^Deke Kassabian, deke@ee.rochester.edu or ur-valhalla!deke Univ of Rochester, Dept of EE, Rochester, NY 14627 (+1 716-275-3106)