how source address can be changed in packet

payal_shah · 03-28-2005, 06:19 AM

hello,

i want to change a source address in packet and then send to destination address.
i am using a PCAP library so i come to know that some packet is coming from suppose 192.160.100.105 address to destination address 200.200.200.201. now my address is 192.160.100.100 and i want to change source address of 192.160.100.105 to 192.168.100.100.

can anybody suggest me any solution?

3-1415 · 03-29-2005, 01:55 AM

try to use NAT from iptables packet.
may be start here: http://qtables.radom.org/samples.php
Also with iptables you may change any field in TCP/IP header, including IP's source address. Read Oscar Andersson's "IPTables Tutorial".

payal_shah · 03-29-2005, 04:39 AM

i don't want to use IPTABLES commands
actually i want to implement NAT myself as project work.
i want to capture the packet but not to sniff it.
how to change source address of the packet. at IP layer.
pls send me the solution , its really urgent.

3-1415 · 03-29-2005, 06:56 AM

...there used to be a good example in William Stevens's "UNIX Network Programming. Networking APIs", chapter 26. Exactly what You need.
The sources to this book you may find here: http://www.kegel.com/unpv1/
Good luck