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cpcappacket-capturepacket-sniffers

pcap only picking up on new connections

I wrote a very simple C program to do a packet capture using pcap. Thing is, it only picks up on a small subset of my network activity. (I think the pattern is that it only picks up on new TCP connections.)

For instance, it picks up on a bunch of packets when I do a GET request with a browser or with wget, or when I start up my X-Chat IRC client and connect.

However, when I leave my IRC client running it doesn't pick up on the packets corresponding to text messages. Similarly, it doesn't pick up on ARP broadcasts on my home network, or ping packets when I ping a website.

I am wondering why it is only picking up on this small subset of the packets I am sending/receiving. Here is my code. I am grateful for any feedback.

Code: http://pastebin.com/QDHRy6jM

Solution

  • Fixed it. When I change my TIMEOUT value from -1 to something else it works (ie it picks up on all network activity). Don't really know what's going on there (haven't thought about it much yet) so if someone does please holla.