Listen for ICMP packets in C#

Question

I have a SIP application that needs to send UDP packets to set up the SIP calls. SIP has a timeout mechanism to cope with delivery failures. An additional thing I would like

Answer 1

So you want to pick up the dest unreachable return icmp packet programmatically? A tough one. I'd say the network stack soaks that up before you can get anywhere near it.

I don't think a pure C# approach will work here. You'll need to use a driver level intercept to get a hook in. Take a look at this app that uses windows' ipfiltdrv.sys to trap packets (icmp,tcp,udp etc) and read/play with them with managed code (c#).

http://www.codeproject.com/KB/IP/firewall_sniffer.aspx?display=Print

• Oisin