On 01/31/2011 12:52 PM, Jim Webster wrote: > netfilter@xxxxxxxxxxxxxxx > > On Sun, Jan 30, 2011 at 6:00 PM, Patrick McHardy <kaber@xxxxxxxxx> wrote: >> On 30.01.2011 12:07, Jim Webster wrote: >>> Hi. I am new to the list and also fairly new to iptables and >>> netfilter. Linux and programming - am familiar with. >>> Have been tasked to provide a way to move MSMQ (DCERPC?) traffic thru >>> our firewall. >>> The firewall is a CentOS iptables based box. >>> >>> Unfortunately, I do not zet have the customer Wireshark trace showing >>> the traffic, specificallz where the address (and port) is supposedlz >>> sent in the pazload. >>> >>> A knowledgeable iptables/firewall person on our team has suggested we >>> require a netfilter helper routine (ala the ftp connection tracking). >>> >>> It seems to me however that instead, some tzpe of adaptive firewall >>> technique is required to do this - opening a new NAT for the IP/port >>> sent in the pazload and closing it when done. >>> >>> If so, can this be done by a simple user app - perhaps a proxy, or >>> should it be in the loadable kernel modules as the ftp connection >>> tracker is? >> >> Yes, you'll need a connection tracking helper that is able to >> parse the DCERPC traffic in order to integrate this with netfilter >> and NAT. I've looked into this a while ago, but due to the >> complexity of the protocol it is non trivial. >> > > Thanks for replz. Scares me a bit when a member of Netfilter team > sazs non trivial :-). > My next step will be to dissect the ftp_conntrack (or other conntrack > routine) to see how it works. Also, think I must dive into the > iptables source code to see how to dznamicallz add/remove the NAT > rules for the protocol. > > At first, after reading this > http://www.faqs.org/docs/gazette/firewalls.html thought I might be > able to do it with a simple proxy in userspace. > > I have much to discover and appreciate anz guidance. Hopefullz, when > (no option for if) this is successful, it will be made available to > others. I am half-time so will take me a while. > > Thank zou, You could have a look at the Suricata IDS or Snort. Both have DCERPC parsers written in GPL C-code. Cheers, Victor -- --------------------------------------------- Victor Julien http://www.inliniac.net/ PGP: http://www.inliniac.net/victorjulien.asc --------------------------------------------- -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
