Topic: Bad TCP checksum

[chrislaurie]

Hi All

I just checked my logs and it has loads od entries like this one:


Oct 31 19:50:44 greenroof1 pppoe[21895]: Bad TCP checksum 428d

An extract of the log when it started (but it has carried on like this all day it seems):

Oct 31 09:39:53 greenroof1 squid[4020]: ctx: enter level  0: 'http://www.pcmstatistieken.nl/pcm/trouw/s?Laatste_nieuws_Novum_ANP.binnenland.Zwijgende_echtgenote_incestpleger_vervolgd&ns__t=1162280286754&ns_referrer=http%3A//www.trouw.nl'
Oct 31 09:39:53 greenroof1 squid[4020]: WARNING: found whitespace in HTTP header name {Cache Control: no-cache}
Oct 31 09:39:53 greenroof1 squid[4020]: ctx: exit level  0
Oct 31 09:39:53 greenroof1 squid[4020]: WARNING: found whitespace in HTTP header name {Cache Control: no-cache}
Oct 31 09:40:48 greenroof1 squid[4020]: ctx: enter level  0: 'http://www.pcmstatistieken.nl/pcm/trouw/s?Laatste_nieuws_Novum_ANP.binnenland._Van_Gogh_kort_voor_moord_vervloekt_door_imam_&ns__t=1162280342035&ns_referrer=http%3A//www.trouw.nl/laatstenieuws/ln_binnenland/article527825.ece/Zwijgende_echtgenote_incestpleger_vervolgd'
Oct 31 09:40:48 greenroof1 squid[4020]: WARNING: found whitespace in HTTP header name {Cache Control: no-cache}
Oct 31 09:40:48 greenroof1 squid[4020]: ctx: exit level  0
Oct 31 09:40:48 greenroof1 squid[4020]: WARNING: found whitespace in HTTP header name {Cache Control: no-cache}
Oct 31 09:42:41 greenroof1 pppoe[21895]: Bad TCP checksum e4ce
Oct 31 09:42:41 greenroof1 pppoe[21895]: Bad TCP checksum 2dda
Oct 31 09:42:44 greenroof1 pppoe[21895]: Bad TCP checksum 1855
Oct 31 09:42:44 greenroof1 pppoe[21895]: Bad TCP checksum f010

Can anyone tell me what this is about?

Cheers

Chris Laurie
The pump don't work 'cause the vandals took tha handles.

[mmccarn]

I get a few of these but they don't impact my network performance.

There are some mentions on other sites about problems with pppoe and "Header Compression" possibly causing a problem where the connection gets out of sync and will not work again until physically broken and re-established.

ppp is designed for a serial connection where there is no chance of packet re-ordering, and header compression assumes that there is no packet re-ordering, but pppoe connections can have re-ordered packets, after which the packet headers & packet contents no longer match.

[chrislaurie]

Thanks for the response. I just checked back and I only received a handful in the last week or so. When I posted the original question I had loads and loads of them.

I use ADSL, is there and alternative to ppp? I suspect I'm in the hands of my local final link provider

Chris Laurie
The pump don't work 'cause the vandals took the handles.

[mmccarn]

Verizon allows you to forgo PPPoE authentication on a DSL/ADSL/FiOS connection if you get a fixed IP address from them for extra $$$.  Other vendors may have similar programs...