Ethereal-dev: Re: [Ethereal-dev] reassembling TCP even if checksums are incorrect

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From: Ulf Lamping <ulf.lamping@xxxxxx>
Date: Thu, 21 Jul 2005 16:58:35 +0200

LEGO <luis.ontanon@xxxxxxxxx>, Ethereal development <ethereal-dev@xxxxxxxxxxxx> schrieb am 21.07.05 15:45:54:
> 
> I have some captures made on a sun in which TCP checksums are
> incorrect for every packet (They are probably calculated after they
> are passed to snoop, the service works OK so on the wire I assume
> those are correct).

I've seen the same problem on other (win32?) machines too.

> 
> Is it OK if we add a prefererence to TCP so it can ignore checksums
> when reassembling in that condition?
> 

I've also thought about that and yes, I think it's a good idea.

Questions: 
- at which layer/protocol to put this pref? probably TCP
- how to name it, suggest: "Try reassembling TCP streams even if TCP checksum is bad"
- which default behaviour to choose (I personally would prefer "Yes", changing the current behaviour, as bad TCP checksums seems to be a common problem. However, other's may disagree)

Regards, ULFL
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