Date: Thu, 12 Oct 2006 01:08:15 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Spiros Papadopoulos <spap13@googlemail.com> Cc: freebsd-questions@freebsd.org Subject: Re: Problems with ipfw and ssh Message-ID: <20061011220815.GA83773@gothmog.pc> In-Reply-To: <dab71e150610111453m39c6bdb8ia846b3c4b39c4e08@mail.gmail.com> References: <dab71e150610111453m39c6bdb8ia846b3c4b39c4e08@mail.gmail.com>
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I removed freebsd-ipfw from the recipient list. Please keep `general' questions in freebsd-questions. The freebsd-ipfw list is, as far as I know, used for *development* of IPFW; not questions. On 2006-10-11 22:53, Spiros Papadopoulos <spap13@googlemail.com> wrote: > Hi, > > I am trying to configure a firewall using ipfw for a machine running > FreeBSD 5.4. Without NAT. > > I am nearly a newbie on this (since i never had time until now..) but > still i believe i understand exactly the concepts and what needs to be > done. Except the manual page and chapter 26.1 in the handbook I am > using good references such as: > > http://www.freebsd-howto.com/HOWTO/Ipfw-HOWTO > > I need to connect remotely to the machine using ssh and this is where > i get the problem: > > Initially i can connect properly using a normal user account. When > later i am trying to su to root it does nothing and the connection > closes. Can you show us the full IPFW ruleset you are using? > I have ipfw enabled in the kernel to deny everything by default. I > have used both (one at a time) the following rules concerning ssh, in > /etc/ipfw.rules and also other combinations, such as taking off setup > and keep-state etc etc which would then make my firewall stateless as > far as i understood, which is something i don't want anyway. > > ${addcmd} 300 allow log logamount 5 tcp from any to me 22 setup keep-state > - > ${addcmd} 300 allow log logamount 5 tcp from any to any ssh keep-state The second seems wrong, unless you also have 'setup' rules elsewhere. > In a first investigation (not thorough) i found this post: > http://www.freebsdforums.org/forums/showthread.php?t=21876 > where from, i cannot realize what is wrong or how to fix this. The initial ruleset of this forum thread has a few bugs, which I'm not interested in pointing out one by one right now. Just ignore most of it. > I run the sshd in debug mode and below is the portion, for when i am trying > to su to root > > /* sshd -d */ > Write failed: Permission denied > debug1: do_cleanup > debug1: PAM: cleanup > debug1: do_cleanup > debug1: PAM: cleanup > debug1: session_pty_cleanup: session 0 release /dev/ttyp7 Now we're getting somewhere. Please post your *FULL* ipfw ruleset so we can try to find out why/when/where packets can be blocked.
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