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, -- Jim -- 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
