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Date:      Thu, 4 Nov 1999 23:24:44 +0100
From:      Juergen Lock <nox@jelal.kn-bremen.de>
To:        freebsd-security@FreeBSD.ORG
Subject:   nmap portscan hangs X server?
Message-ID:  <19991104232444.A590@saturn.kn-bremen.de>

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I just installed nmap from ports and found out when i simply do a

	nmap 127.0.0.1

 it'll hang the X server. (XFree86, not the latest version, mind you)
Can anyone reproduce this?  Be sure you can login over the net (or a
serial tty) when you try this to be able to reboot the box as the
console will be unusable after this.  (otherwise you'll have to reset
and wait for the fsck.)  Btw a

	nmap -sS -O 127.0.0.1

 will not hang it, which is what i tried first (from xnmap.  this is
probably to be expected as listening processes won't notice this type
of portscan.)

 Anyway, for now I'm starting it with -nolisten tcp...  (X has already
been blocked from the outside in ipfw so i might as well do that too.
but if you do need to display remote programs and ssh is too slow...)

 Oh and I tried some searching on the web but found no mention of this.

 Regards,
-- 
Juergen Lock <nox.foo@jelal.kn-bremen.de>
(remove dot foo from address to reply)


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