Linux: Turn NIC auto-sensing off?

The switches on our internal network are all set to 100 Mbps. We are having trouble with an intermitten connection on one of our Linux servers. The server will drop the connection, but logging into the console and visiting a web page will bring it back up. No other action is needed.

Is there a way to set the network card to turn 'auto sensing' off and hardcode it to 100 Mbps? Would that setting be in the 'ifcfg-eth0' config file? Does this possibly sound like it might be the problem?

Thanks.

If the switch is set static and the PC is set auto it will cause this behavior in most sercumstances. what version of linux are you running?

juniperr,

Thanks for the reply. We're running SUSE Linux Enterprise Server 8. There's not place in YAST to turn auto-sensing off. I was just wondering if I could do it elsewhere, i.e. a configuration file. If not, would be setting that port on the switch to 'dynamic' work?

Thanks.

do a "man mii-tool" leave out the ""

you can also see what it is running at with mii-diag

yes setting the switch to auto should fix the problem SuSE is good at auto detect. however, in most cases unix and novell like static speed and duplex the best, auto negotiate is only stable in microsoft platforms and iffy on linux ( never ever mix the two with any platform ie. setting server speed/duplex static and auto on switch or vise versa). on your switch turn it to auto, rebbot server or ifconfig down the interface then back up and then check for framing errors and or CRC errors if they are not incramenting you fixed the problem. you didnt mention what type of switch so I cant give you details on resetting the counters or checking for errors.

Duplex, speed settings and autonegotiation are hardware protocols, so any problems with them are the fault of hardware or drivers, not really the OS. The best way to solve the problem is what juniperr suggested, set the switches to auto. The autoneg protocol does not specify what to do when both devices are capable of auto but one is hard set, that's what causes the problem.

As for the changing the settings on the NIC on the SuSe server, most NIC manufacturers have software for changing the setting on the ROM chip on the NIC itself. OR, it should be possible to pass the parameter to the driver (something like speed=100 duplex=on, depending on the driver) at load time. You can get a list of what settings to pass to the module by using modinfo (eg, modinfo eepro). If the driver is compiled into the kernel, then just recompile with the setting you want.

As to where Suse loads modules from, if you find out let me know. I poked around the init files on my Suse 8.1 server for a half hour and I can't find them. Also can't find anywhere to do this in YAST, though I suspect theres a way. (Slackware is so much easier... but I can't run NLS on it ).

thanks for the help. I ened up setting the port on the switch (Catalyst 2950XL) to dynamic and it has gone down today.

As mjm1231 suggested, I know that the speed was hardset on the card and assumed there must be a parameter to pass to the card through the driver to set the speed, but I didn't know what it was. Aslo, I did look in YaST first for the setting, but like you, could not find a setting (which is why I posted here). I don't know where SuSE loads modules from, but the eth configuration is stored in /etc/sysconfi/network/ifcfg-eth0 (ifcfg-eth1, etc.).

juniperr, how do I check for framing and CRC errors..

Thanks for all your help.

first clear the counters by typing "clear counters" then do a " show int | i CRC ", this will scroll all interface CRC errors they should all be 0 after clearing them. keep typing in the command and see if any incrament if not your golden. replace CRC with "framing" or just "errors" for others.

I think I found where Suse loads mudules from... Try adding the settings to the line in your /etc/modules.conf file.