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DNS Checksum

asked 2018-10-20 17:48:35 +0000

Hi I'm still learning how to use wireshark properly. Can you help me explain how to calculate the DNS checksum? Is it the same way we calculate UDP checksum?

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What field are you referring to exactly? What display filter matches this field (you can find it in the lower left corner of the Wireshark window)?

Jaap gravatar imageJaap ( 2018-10-21 08:58:48 +0000 )edit

I use dns filter. In the UDP line, there is a checksum. I want to verify the checksum but I can't figure it out how

Yudistryan Izhar gravatar imageYudistryan Izhar ( 2018-10-21 09:01:47 +0000 )edit

In the UDP line, there is a checksum

That's the UDP checksum, not the DNS checksum. DNS is transported over UDP (and sometimes over TCP); the UDP checksum in a DNS-over-UDP packet is part of UDP, not DNS.

Guy Harris gravatar imageGuy Harris ( 2018-10-21 21:14:48 +0000 )edit

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answered 2018-10-21 18:09:29 +0000

Jaap gravatar image

The UDP checksum is "Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets.", as per RFC 768. See also the TCP/IP Guide, or wikipedia.

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Asked: 2018-10-20 17:48:35 +0000

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Last updated: Oct 21 '18