Raw sockets to receive IP packets

ambuli
ambuli used Ask the Experts™
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Hi there,
I am trying to open a raw socket to capture IP packets.
When I use the option, "IPPROTO_TCP" I am able to capture the tcp packets, and similarly IPPROTO_UDP works for udp packets.  However, when I use IPPROTO_RAW I am not capturing any packets.  I am using Ubuntu Linux.  What could be wrong here?

When using IPPROTO_IP, I am getting an error( 93 - Protocol not supported)

 sock_raw = socket(AF_INET , SOCK_RAW , IPPROTO_RAW);

thank you.
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Top Expert 2016
Commented:
an IPPROTO_RAW protocol is for send only. if you want to receive raw messages you should use htons(ETH_P_ALL) for protocol.

see
http://ubuntuforums.org/archive/index.php/t-1292481.html

for sample code or man pages

http://manpages.ubuntu.com/manpages/lucid/man7/raw.7.html

http://manpages.ubuntu.com/manpages/lucid/man7/packet.7.html

for more information.

note, raw sockets normally were used to implement a new ip4 protocol or by net sniffers. they are badly portable and you may get issues with installed security mechanisms.

Sara

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