Re: solaris rshd question

From: David Mathog (mathog_at_caltech.edu)
Date: 03/22/05 

Date: Tue, 22 Mar 2005 08:43:36 -0800

Barry Margolin wrote:
> In article <d1nnfd$e4a$1@naig.caltech.edu>,
> David Mathog <mathog@caltech.edu> wrote:
>
>
>>Has anybody ever solved this before? It looks like it might
>>be necessary to modify rsh so that it can tell the firewall
>>to open the second port.
>
>
> The firewall should scan rsh packets to see where the second port number
> is sent to the server, so that it can open the port. This is analogous
> to the way firewalls monitor FTP control connections, looking for the
> "PORT" command that tells the server to open a data connection back to
> the client.

That was a good clue. After some googling it turns out this
is called "connection tracking" in iptables parlance. For it
to work a matching iptables module must exist. In this case it's

    CONFIG_IP_NF_RSH

Unfortunately this option doesn't exist in 2.6.8-1, which is
the kernel version I'm using. It's apparently in 2.6.11. Not
sure when it was added or if the code is backwards compatible
with earlier kernels.

Thanks,

David Mathog
mathog@caltech.edu

Relevant Pages

  • Re: solaris rshd question
    ... > be necessary to modify rsh so that it can tell the firewall ... The firewall should scan rsh packets to see where the second port number ... to the way firewalls monitor FTP control connections, ...
    (comp.sys.sun.admin)
  • [patch] move ipfw logging to after syslogd
    ... We have a problem that on our busy firewalls, a boot and shutdown ... can be delayed by up to 20 minutes by the kernel printing log ... most kernel activity appears to be suspended by outputting ipfw ... echo 'Firewall rules loaded.' ...
    (freebsd-current)
  • Re: Linux firewall on P166
    ... Which is it, ipchains or iptables? ... gives you a much stronger firewall. ... It's difficult to do much with 4MB RAM, ... > of a specially-tailored kernel. ...
    (comp.os.linux.networking)
  • Re: Linux firewall on P166
    ... Which is it, ipchains or iptables? ... gives you a much stronger firewall. ... It's difficult to do much with 4MB RAM, ... > of a specially-tailored kernel. ...
    (comp.security.firewalls)
  • Firewall-easy setup difficulties
    ... I'm using debian unstable, 2.6.7 kernel. ... kernel support ... NO ipchains list, firewall kernel support? ... HOME USER CONFIG ...
    (Debian-User)