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TCP Checksum errors


Ok I read this wiki article

Wireshark Wiki TCP checksum errors

The checkbox was already deselected and yet I am still getting TCP packets with bad header checksums. Its always the TCP packets that are leaving my computer and not the ones coming in.

is there another setting I am missing?

Error looks like this

Header Checksum: 0X0000 [incorrect, should be 0xb2ae]

I gather this is TCP offloading as there is settings for this in my adapters configuration setups.

asked 05 Nov '10, 19:16

Treborprime's gravatar image

accept rate: 0%

2 Answers:


The line "Header Checksum" is from the IP protocol details, not the TCP protocol details. So if checksums at the IP layer are calculated by the NIC as well (as can be indicated by the fact that every outgoing packet has a bad checksum), you need to disable checksumming in the IP protocol preferences too.

answered 06 Nov '10, 03:28

SYN-bit's gravatar image

SYN-bit ♦♦
accept rate: 20%


Eric gave me your link on your HeaderChecksum. Got the same thing going here, Only mine are going out fine. It's what's coming in. Plus all Packets are Malformed and Errored or Warned. But here again the outgoing is fine. Plus many other server problems at my ISP. From their DNS, DHCP, and their Exchange Server. I don't think it could be possible their Routered relays are the problem. Took them 9 months just to get my contracted service speed (bandwidth) set right. Which literally amounted to turning a switch on. I can't imagine what getting this correct will take in an amount of time! I'm the Wireshark on PPPoE?

answered 08 Dec '10, 16:50

Algonquian_Cougar's gravatar image

accept rate: 0%