Author Topic: Host Contact Problems  (Read 6089 times)

Da_Blitz

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Host Contact Problems
« on: March 31, 2007, 02:31:31 am »
Well i never thought i would be asking someone else for linux help but i guess its my last option  ethire that or reinstall windows

anyway i am having a wierd problem, at first i couldnt ssh into my server (on the internet (pocketnix.org)) however i soon relised i couldnt contact any service on my host from my OS

my quick patch was to ssh into another server and then from there ssh into the pocketnix server, works fine but port fowarding is a b#@% in that senario

anyway i tested trying to contact the server on several machines, works on my PDA (behind the same nat as my home PC) works on a debian VM on my machine (What the?!?!?) however dosent work on any other fedora core 6 machines

now it might have been a kernel update (thinking congestion control or one of those options that says "dont enable me or i cant talk to 1/2 the internet", yes there is one of those in the kernel) or a ssh update

i have tried everything related to mtu size changing however running wireshark on the services seems to indicate that the connection is made and works fine untill the connection "get serious" ie with imaps it cuts off after the ssl handshake, ssh when auth protocols are bieng exchanged "SSH2_MSG_KEXINIT" and with http after the GET command

i recive no errors until i close the connection in which case i get retransmitted packet errors

i am thikning its a problem with my router, to say its unreliable is an understatment, i drop the connection on a regular baisis (some cases every 5 mins under load) and cant get rid of it as its the adsl modem as well (last time i let some one else handle the "details")

any ideas, im guessing its a fedora only problem (seen enough of those) and am willing to change however i am looking at changing to a 64 bit distro that works, fedora wont boot, debian hangs at the language selection part of the install and misc bad things happen with all teh other distros

beginig to think the computer haunted, anyway if you have any ideas pleas reply, im at my wits end after the problems that have plauged me in the last week (kernel that crashes x secconds after boot, you can time your watch to it and a usb hub between the keyboard and PC that wasent getting properly reset by the bios and hanging the bios leaving me 2 days of diagnostics before i replugged the hub and restarted it)
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Da_Blitz

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Host Contact Problems
« Reply #1 on: April 02, 2007, 07:08:32 am »
Ok fixed, it was a MTU problem

well i decided to fiddle  and set the mtu to 400, guess what it cra#s out earlier so:

i have a gigabit ethernet card and thought "why not try jumbo packets on a network that dosent support them" (ie 10/100) just for fun

well setting the mtu to 9000 stuffed up at the same point but setting it to 90000 and it works like a charm, would someone pleas explain this to me as i was under the impression that the kernel would cut up the message automatically if its above the mtu, however it seems that it dosent do that on my PC (confirmed on another fedora not running xen

perhaps its a tso prolem? bit out of my depth at the moment but it means i dont have to do the double port foward (log into someone else machine and then to my server) so it should help speed up the setup, next comes vpn !!:)
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Da_Blitz

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Host Contact Problems
« Reply #2 on: April 04, 2007, 07:33:48 am »
it gets wierder, it now works without ajusting the MTU

well thanks for listening the 60 or so people who visited this thread, starnge things do indeed happen and i just hit one

signing off
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Gemini Order: #95 (roughly)
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