Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
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I am a bit of a Linux novice, have been running RH 7.2 for a while but haven't really had to get my hands that dirty with it.
Issue with networking 2 machines (through dedicated switch, no external connections, RH 8 and Win XP), ping works but only under the most bizarre circumstances. Boot both machines normally and attempt to ping each other and get 'Destination Host Unreachable' message from Linux and time out from XP. However fire up Ethereal on the Linux box, start capturing traffic from eth0 and everything works fine, pings in both direction. Stop the capture and the errors reappear!
What is ethereal doing as it is capturing traffic that isn't there normally?
Do you have any ipchains rules defined by default? At some point RH began asking how you want your firewall to be config'd during install. If you specify medium or high, then you may be blocking the ping requests.
That wouldn't explain why the ethereal is allowing packets to come thru, unless it is setting eth0 to promiscuous mode. (different concept altogether).
Have not set anything up manually for either the RH8 network card or the XP one.
The netgear switch that I am using is showing both connections at 100mb and when I ping the lights flash on the switch for the correct ports. The speed that the cards are operating at shouldn’t be an issue should it?
Re duplex settings for the network cards – again haven’t set anything manually although I know that the XP machine is running full duplex, my impression is that with the switch I am using speed and duplex mode shouldn’t be an issues – the switch autonegotiates etc. Might be wrong though!
Is there anything specific that I can check to rule this out?
Does RH 8 use ipchains or tables, think it is the latter – concepts should be similar?
When I installed (should say reinstalled !) conciously set the security option to ‘No Firewall’ however the strange thing is that when I go into the RH desktop and run the graphical security applet it tells me that the security setting is High and won’t let me change it, weird!
Suspect that there might be some firewall issues at the bottom of this (that’s why I tried to reinstall with none). Have never played with firewalls, any clues re how I can analyse \ resolve?
Originally posted by John_L
Does RH 8 use ipchains or tables, think it is the latter – concepts should be similar?
I have been using 7.3 and it had both installed. I just got my 8.0 up and running today, and I see that they have dropped ipchains.
Quote:
Suspect that there might be some firewall issues at the bottom of this (that’s why I tried to reinstall with none). Have never played with firewalls, any clues re how I can analyse \ resolve?
run the following command on your running system;
Code:
iptables -L
This will tell you what rules are defined. You may want to move this post to the Linux-Security forum for better assistance on interpreting any rules that are defined.
If you just want to flush the table for troubleshooting, then use the -F option with no arguments.
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