[ntp:questions] Re: Strange IP flags set in NTP conversation
kudzu at tenebras.com
Wed Oct 15 00:20:46 UTC 2003
Vernon Schryver wrote:
> Do you have an exgesis of DS RFCs showing 0x10 is invalid?
When looked at as a DS field, the upper six bits are the differentiated
services code, and 0x04 is undefined. 0x04 in the upper six bits is
the same as 0x10 in the byte if I have counted my bits correctly. I
suppose I shouldn't look at these for UDP anyway. But there is malware
that uses these as a subliminal channel.
> There are plenty of routers that honor the old TOS values.
I suppose those same routers don't handle explicit congestion
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