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I have RDP session setup between 2 clients but I am getting checksum error when they are doing TCP 3 way handshake at the time of ACK I see below error.

Can someone please help me understand why I am getting that? Header checksum: 0x0000 [incorrect, should be 0xb46a (may be caused by "IP checksum offload"?)]

Thanks for help.

asked 28 Feb '13, 22:58

m_1607's gravatar image

accept rate: 0%

edited 01 Mar '13, 07:20

cmaynard's gravatar image

cmaynard ♦♦

It's an artefact of the capture mechanism on your host. See the wiki page on Checksum Offloading for more info.

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answered 01 Mar '13, 02:36

grahamb's gravatar image

grahamb ♦
accept rate: 22%

Thanks for the link, i am still unsure if I should disable Offloading. I guess its worth a try

(04 Mar '13, 07:47) drewdin

Unless you have a buggy driver/NIC firmware that doesn't do the checksums correctly you're probably best to leave it on for performance reasons.

If the "errors" reported by Wireshark are bothering you, turn them off in the preferences for each protocol with the "Validate the xxx checksum if possible" setting.

(04 Mar '13, 08:02) grahamb ♦

good idea, ill just turn them off in WS, thanks!

(04 Mar '13, 10:32) drewdin

Some drivers had the RX checksum offloading bug fixed. Bad cabling and programmatic-ally disabling and reenabling the card as well as getting new drivers addressed the issue. There's more in depth details and analysis available from sources here:

Windows / Linux: The local device name is already in use. This connection has not been restored and IP checksum offload

Cheers, TK

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answered 17 Aug '13, 16:55

TomMDS's gravatar image

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question asked: 28 Feb '13, 22:58

question was seen: 93,428 times

last updated: 17 Aug '13, 16:55

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