Penetration Testing mailing list archives
Re: Any way to automatically change arbitrary headers of IP packets on-the-fly?
From: João Paulo Caldas Campello <protecao () gmail com>
Date: Fri, 15 Apr 2005 20:32:45 -0300
On 4/13/05, Kary Rogers <kdr7 () msstate edu> wrote: Kary,
I think you can do this with divert sockets. I've used divert sockets on FreeBSD and MacOS X to change TCP flags. There's a how-to for linux: http://www.faqs.org/docs/Linux-mini/Divert-Sockets-mini-HOWTO.html
Very nice. I've read the documentation and it seems easy. Thanks a lot. Some guys provided me a lot of links, including documentation of the "libipq" API and libraries written in Perl and Python, so it will be much more easier to write userspace code to deal with the IP packets and flush it back to netfilter, who will bring back the packet to its normal flow. Thanks to all the guys who helped me, either pointing some links and documentation or even just discussing the topic. Some other useful links: * IP QUEUE*: - netfilter can feed userspace using IPQUEUE: * http://www.crhc.uiuc.edu/~grier/projects/libipq.html - Perl: * http://www.intercode.com.au/jmorris/perlipq/ - Python: * http://woozle.org/~neale/src/ipqueue/ The "DIVERT sockets" and "-j QUEUE" target approaches are similar: you can use iptables' rules to match some packets and flush them to userspace, where you can mangle the entire IP packet as you like and send it back to netfilter, thus continuing their normal flow onto the stack. I think now it'll be much easier to address this problem, either using DIVERT sockets or the IPQUEUE libraries for Perl and Python. Thanks again and cheers, João Paulo.
Current thread:
- Any way to automatically change arbitrary headers of IP packets on-the-fly? João Paulo Caldas Campello (Apr 12)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? Lynx (Apr 13)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? Vladimir Parkhaev (Apr 13)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? Kary Rogers (Apr 13)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? João Paulo Caldas Campello (Apr 17)
- <Possible follow-ups>
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? Sebastian Muñiz (Apr 13)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? Foundation Linux (Apr 13)
- Re: Any way to automatically change arbitrary headers of IP packets on-the-fly? João Paulo Caldas Campello (Apr 17)