IP packet forwarding

chamithranaweera · 02-27-2007, 04:23 AM

Is there any method to forward network(IP)packets using pcap.h header file .We are using libpcap and tcpdump Is there any method to do it or do we need to use another tool instead of libpcap.

acid_kewpie · 02-27-2007, 04:28 AM

well firstly a header is just a list of function names and variable. it doesn't do a single thing. if you wish to actually utilize libpcap as a whole, then that is, as the name suggest, for packet capture, not forwarding.

chamithranaweera · 02-28-2007, 03:40 AM

Well thank you for the details.
Do I need to use onather method to packet capturing
But how a linux machine would do it?I thought it was pcap.h file have necessory functions.
Please can you show me the way to do packet capturing.I really need to do it.

vishamr2000 · 02-28-2007, 03:54 AM

Hi there,

U can intergrate both sniffer and packet sending capability in a program. Or u can have separate programs - one for sending packets and one for sniffing. U can pass the packets captured and then pass then to the packet sending program (using sockets).

If you are only interested in packet forwarding, you can use IPTables that can redirect your traffic to another PC or network. There is also Ebtables (dnat target)..it depends on wat you are trying to do. Provide more details if u can..

Warm regards,
Visham

chamithranaweera · 03-01-2007, 03:42 AM

Hi there,

Plz can you give me some examples how to do this thing? or can you give me some codes that do the forwording(capturing and forwording)
plz help me I am structed in my program.

vishamr2000 · 03-02-2007, 01:07 AM

pcap for capturing:
http://reactor-core.org/libpcap-tutorial.html
http://www.tcpdump.org/pcap.htm
http://yuba.stanford.edu/~casado/pcap/section1.html

For socket programming:
Look for Beej's Guide

For the forwarding part, you'll have to provide some more info as I dont know the system you're putting in place or what you are trying to achieve. The solution will depend on what you want to achieve

Warm regards,
Visham

chamithranaweera · 03-06-2007, 03:09 AM

Hi there,
thank you for the infomation.it is really worth.
Actually we design a software router using Linux operating systems besides the kernel routing method in Linux.

We are using Red hat Linux Enterprise edition 4.0 as our core operating system.

Actually we struck in the forwarding part.So plz help us to get on with the frowarding part.