Per RFC792 (http://www.faqs.org/rfcs/rfc792.html):

"The checksum is the 16-bit ones's complement of the one's complement sum of the ICMP message starting with the ICMP Type. For computing the checksum , the checksum field should be zero. This checksum may be replaced in the future."

Therefore, simply replace your '$chk += $short;' with '$chk ^= $short;' and it should work.

BTW: Thanks for the code! :-)

Happy Hacking!

In reply to Re^3: icmp code, w/o Net::Ping and problem by Knom
in thread icmp code, w/o Net::Ping and problem by doctor_moron

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