From owner-freebsd-hackers Mon Nov 18 12:52:35 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id MAA10824 for hackers-outgoing; Mon, 18 Nov 1996 12:52:35 -0800 (PST) Received: from isbalham (isbalham.ist.co.uk [192.31.26.1]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id MAA10819 for ; Mon, 18 Nov 1996 12:52:32 -0800 (PST) Received: from gid.co.uk (uucp@localhost) by isbalham (8.6.12/8.6.12) with UUCP id UAA24026; Mon, 18 Nov 1996 20:49:33 GMT Received: from [194.32.164.2] by seagoon.gid.co.uk; Mon, 18 Nov 1996 20:42:47 GMT X-Sender: rb@194.32.164.1 Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Mon, 18 Nov 1996 20:42:27 +0000 To: Marc Slemko , Robert Shady From: rb@gid.co.uk (Bob Bishop) Subject: Re: BoS: Exploit for sendmail smtpd bug (ver. 8.7-8.8.2). Cc: roberto@keltia.freenix.fr, freebsd-hackers@FreeBSD.org Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk At 8:34 am 18/11/96, Marc Slemko wrote: >[moved to -hackers from security. It started with a discussion of >sendmail with uucp; I stated that sendmail still tries to use DNS no >matter how you configure it and you have to recompile it to make it stop.] > >On Mon, 18 Nov 1996, Robert Shady wrote: > >> > Incorrect. It RUNS without DNS but still TRIES to use it. If you really >> > don't have IP connectivity, then difference doesn't matter because it >> > still works when the lookup fails, however it still does try and the >> > difference does matter if you have partial IP connectivity. I have a >> > system setup with nocanonify and all the other config file tweaks I know >> > of, and it still tries to use DNS as a tcpdump shows quite clearly. This >> > system is running 8.7.5, so things may have been changed in more recent >> > versions but I can't say for sure; if this has changed in more recent >> > versions, please let me know. >> > >> > I _think_ the define that needs to be set to 0 is NAMED_BIND, but don't >> > recall for sure. This has been gone over before on the lists. >> >> Out of curiosity, what interface exactly are you looking at if you aren't >> running tcp/ip? > >I am running TCP/IP, however only sometimes; ie. a dial on demand >connection. If it isn't recompiled, no matter how you configure it, >sendmail will try a DNS lookup for each bit of mail it receives, causing >the dial on demand link to come up. I am looking at the ppp (tun0) >interface. If you don't have IP running, or you don't have a route to a >nameserver, or you don't have a nameserver, you won't notice the lookup >but it still tries and, in this case, fails immediately. Run a caching-only nameserver locally? -- Bob Bishop (0118) 977 4017 international code +44 118 rb@gid.co.uk fax (0118) 989 4254 between 0800 and 1800 UK