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Network problems?

 
Kyle D. Harris
Regular Advisor

Network problems?

What all does one need to see the outside world after installing and setting up the static ip as well as /etc/hosts ...? I'm just trying to pinpoint why i can't ping or ftp out and i can't see my box from other servers on the same network. Any ideas are appreciated. Thanks!

Kyle
14 REPLIES 14
Mark Grant
Honored Contributor

Re: Network problems?

if "ifconfig eth0" shows the following things

inet addre:xxx.xxx.xxx.xxx (your ip address)
Mask: xxx.xxx.xxx.xxx (the netmask for your network)

UP BROADCAST RUNNING MULTICAST

Then the network card is probably ok and running (confirm by pinging your own ip address) and the problem will be either your cable or the route to other machines on the network.

if your ip address where 10.0.8.77 and you had a netmask of 255.255.255.0 you would need a route as follows from "netstat -rn"

Destination Gateway
10.0.8.0 10.0.8.77 (for other machines on the same subnet as you)
0.0.0.0 10.80.8.11 (assuming this ip is some router or bridge that can get you out the the rest of the world)

Other than that, you should be OK.
Never preceed any demonstration with anything more predictive than "watch this"
Kyle D. Harris
Regular Advisor

Re: Network problems?

I just pinged myself and was 5/5 100 % recieved...

I also have to go through a proxy which i have set up identical to another server that works fine.

I had to get a telephone jack converted to a lan line port. Perhaps they didn't do this correctly ?
Ragu_1
Regular Advisor

Re: Network problems?

What does `route -n' and `ifconfig' say ? Have you restarted your networking daemon after making changes to the /etc/hosts and other networking related files ? What does `iptables -L' say ? Check whether you have plugged in the cables, check our connection to the switch/hub, check whether you are able to ping 127.0.0.1, do a `netstat -nlp' and verify the services runing on your machine. Drink a cup of strong black tea and do `hatha yoga' for 3 minutes!
Share and share alike
Mark Grant
Honored Contributor

Re: Network problems?

The jack plug sounds like a good candidate if the above points are OK.
Never preceed any demonstration with anything more predictive than "watch this"
Kyle D. Harris
Regular Advisor

Re: Network problems?

How do i save to floppy? i saved the output of ifconfig and route to a text editor. I want to put it on floppy to post here.
Sergejs Svitnevs
Honored Contributor

Re: Network problems?

Consult with your system administrator
about your IP address, NetMask and Default gateway which does not cause conflicts with any other device on the network. Make sure that the LAN cable is workable and plugged firmly into your LAN card and the enabled network port.

Regards,
Sergejs
Mark Grant
Honored Contributor

Re: Network problems?

You don't need to put it on a floppy to post here you can just attach the file.

However, if you want to put stuff on a floppy, there are two ways to do it. The first is the easiest but not to flexible. Put a floppy in the drive (it doesn't even have to be formatted I don't think) and go "tar cvf /dev/floppy myfile". The only way anybody can read this is by going "tar xvf /dev/floppy".

The other way is to put a filesystem on the floppy with "mkfs /dev/floppy" and then mount it "mount /dev/floppy /mnt" and then you can copy files back and forth between /mnt (which will be your floppy). You qwould need to remember to unmount the floppy with "umount /mnt" before taking the floppy out or you'll break it.

Alternatively the cheap way, which goes against all my personal philosophies, is to get your self a windows formatted floppy and "mount -t vfat /dev/floppy /mnt"
Never preceed any demonstration with anything more predictive than "watch this"
Kyle D. Harris
Regular Advisor

Re: Network problems?

I have checked and made sure the lan line was plugged all the way in on both sides which it was. I'll check with the lan/wan administrators to see if it's on there side. Thanks to all who responded!

Kyle
Steven E. Protter
Exalted Contributor

Re: Network problems?

In Linux the boot network configuration is in this directory:

/etc/sysconfig/network-scripts

There are files called ifcfg-eth0 for example. It conains the boot settings for the eth0 NIC.

Seems to me this problem is being caused by a conflict between your network settings and the broader network.

You should be able to ping the card from another box and have it work. I think its a good idea to check with network administration, because a duplicate IP address can cause this problem. It also could be a DNS entry for your machine that doesn't match the IP address you configured it for.

good luck Kyle.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Kyle D. Harris
Regular Advisor

Re: Network problems?

Maybe this could make a difference, I'm not sure.

But I have 2 Ethernet cards on this server. I wasn't sure which one is which as far as the lan line being plugged into so i put the same static IP address on both of them in the network device settings. Could this make a difference as far as my problem?
Steven E. Protter
Exalted Contributor

Re: Network problems?

yes Kyle.

ifconfig


On most Linux distributions, you'll get the configuration of all NIC's and virtual ip's on the server.

Its important to have these files be consistent(/etc/sysconfig/network-scripts)

Post the ifconfig output(sanitize it if you must).

I've been through these kind of problems and they can be maddening.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Kyle D. Harris
Regular Advisor

Re: Network problems?

Steven-
It is difficult to post that information on here due to the fact this is my work computer, and the commands are run from the server i'm working on next to me. So I don't have a way to post them online.

But my Eth0 and Eth1 have the same inet addr, bcast, and mask. They have the same because i'm not sure what card my lan line is plugged in.

Kyle D. Harris
Regular Advisor

Re: Network problems?

I'm thinking of disabling one of the Ethernet cards at a time to figure out which one the Lan line is actually plugged into (eth0 or eth1)
Kyle D. Harris
Regular Advisor

Re: Network problems?

TO ALL!

I FINALLY solved the problem. Everything is perfect!! The problem ended up being that since i wasn't sure which of my 2 ethernet cards the lan line was in, i duplicated the settings the same on both cards. Well once i disabled one and found out which one it was plugged into, I activated the one i needed and everything is perfect! thanks so much to all of you!

Kyle