Sending out Ping Requests

Question

Using WinpCap and trying to generate my own ping requests.

On both machines I see the ping request and the only differences between the ones I've generated the ones Windows has generated is my checksum is 0 (been told that's ok) and the identified is 100 instead of an ever increasing value like Windows uses. (I increase each time I try to send a ping request).

Should I paste the hex dump here? :P

EDIT: I guess my question here is to find out what could cause Windows to NOT respond to ping requests that show up as valid in Wireshark.

Answer 1

Yes, you should probably paste the hex dump here.

It could be the fact that the checksum is wrong. Unlike UDP, I believe ICMP (ping) checksum is not optional and should be correct. This is also what I got from RFC 792.

If you want to use WinPcap with .NET, you can use Pcap.Net, which will allow you to create and send any ICMP packet by writing very few lines of code.