modify icmp

[othe]

i want to enter two more fields in the icmp packet so as to send some extra information that i can decide. i suppose it is more easy to enter them at the end of the packet.can anyone knows how to do this?

[Rubberman]

I don't think you can do that. The header formats for ICMP , RFC 792, are clearly defined. Violating them will cause serious problems, I suspect. From the RFC 792 documentation:

Message Formats

   ICMP messages are sent using the basic IP header.  The first octet of
   the data portion of the datagram is a ICMP type field; the value of
   this field determines the format of the remaining data.  Any field
   labeled "unused" is reserved for later extensions and must be zero
   when sent, but receivers should not use these fields (except to
   include them in the checksum).