Date: Mon, 18 Nov 1996 20:42:27 +0000 From: rb@gid.co.uk (Bob Bishop) To: Marc Slemko <marcs@znep.com>, Robert Shady <rls@mail.id.net> Cc: roberto@keltia.freenix.fr, freebsd-hackers@FreeBSD.org Subject: Re: BoS: Exploit for sendmail smtpd bug (ver. 8.7-8.8.2). Message-ID: <v01540b00aeb67a4ec24e@[194.32.164.2]>
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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
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