I am having kind of a unique problem (or at least I think). I had my linux box off of my network for a week or two and when I brought it back up I am running into a problem where I can't ping other devices on my network. The weird thing is that other devices can ping my linux box.

I am pretty new to linux and I was trying to configure the box as a router but was unsuccesfull. I didn't think that I changed enough configurations to do this.

I am wondering if anyone has any ideas, I need this fixed as quickly as possible because I am now at the stage I can implement my server in my business.

I am using this server as a webserver and email server. Right now I can't get the the websites that I have on the box so even though I get a reply from the linux box when I ping it, it isn't responding to other requests.

If someone would like to email or talk directly I would be extremely happy to do so.

Thanks for your help.

Noah

post the output of
ifconfig
route -n
iptables -nvL
iptables -nvL -t nat

good luck.

IFCONFIG:

eth0 Link encap: Ethernet HWaddr 00:60:97:CF:4D:FB
inet addr: 192.168.0.4 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:129 dropped:0 overruns:131 carrier:131
collisions:0 txqueuelen:1000
RX bytes:10240 (10.0 Kb) TX bytes:0 (0.0b)
Interrupt: 11 Based address:0xa000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:3766 errors:0 dropped:0 overruns:0 frame:0
TX packets:3766 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:356328 (347.9 kb) TX bytes:356328 (347.9 kb)


ROUTE -N:

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0eth0


IPTABLES -NVL:

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination

Chain FORWARD (policy ACCETP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination


IPTABLES -NVL -T NAT:

Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination

Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination


Above is the output of the commands that you said I should put in. I do want to let you know that I was case sensive I just capitalized everything for header purposes. I hope this helps because I'm out of guesses. I just uninstalled the NICs that were in the box and made sure that the profile for the NICs weren't there anymore. I did reboots between uninstalls and reinstalls and I am having the same issue.

If there is anything else that you might have me run I would be happy to do it.

Thanks for the help so far!!! I really need this fixed.

Noah

Ok.... I feel a bit stupid but it still isn't working. The whole computer isn't on the network at all. I mean, I can't ping it or ping from it. I have a wireless node on my network pushing out a wireless signal to my surrounding area that I must have gave the 192.168.0.4 address to and that is what was replying. The only thing that doesn't make sense is that it was replying to the host name of the linux box which is RHLINUX.

I have since gave the linux box (RHLINUX) a new IP address of 192.168.0.5 and it still can't ping anything and no other computer on my network can ping it. Basically it isn't on the network at all. Below is how I have my other computers on the network configured and each of them work just fine.

Computer 1 192.168.0.2 (functional)
Computer 2 192.168.0.3 (functional)
Wireless node: 192.168.0.4 (functional)

Linux box: 192.168.0.5 (not functional)

All have the same subnet mask of 255.255.255.0 and the same gateway of 192.168.0.1

I don't know if this new information will help any or not. I am hoping that the above commands will help out. I really don't want to reinstall the OS because there is a piece of software that installed that was kind of difficult to configure.

Thanks again for your help!!!!

Noah

i asked u to post the iptables rules cos it might block network activity. but it is empty and accepts all of requests.

take a look at the errors in TX packets. after u changed the ip of linux have u had same TX/RX errors?

good luck.

Howzit

Well the reason why it responds to RHLINUX is because u are ping the localhost name which is being resolved by you local machine, in other words if u run this Cmdr the results will be the same ping 127.0.0.1. It seems that that it is a physical connection problem. Check the connections between the LAN card and the Transmitter it may be some interference or something like that. If possible try placing a NIC instead of the WLAN card.

cheers

I replaced the network cable thinking it might be that but that didn't work out. I do have lights both on the NIC and the switch that it is plugged into so I don't think that it's a connection problem. About the only other thing that I was going to try physically would be another NIC to see if that helps.

From here I really don't know how to get it on the network or what files to look at to see if they are different than the default. I am thinking about reinstalling the system and going through that pain process because I can't think of anymore avenues.

I guess I know now not to mess around with trying to make a router out of my linux box.

Hi

I would first of all , will check if I can ping to myself . If you can , then will look on the /etc/hosts
file to see if is properly configured . THe machine you are trying to ping must be listed in that
file

Ok..... I've got something for you! I just said screw it and reinstalled the whole OS (Red Hat Linux Enterprise AS v3). You will never guess.... I'm still can't get it on the network. Here is what I know.

Fresh install of OS
Can't grab a dynamic IP from cable router/modem
If I give it an IP it can't ping out or will not reply (says destination host unreachable).
I have tried two different network cards
I have tried three different network cables
I have tried two different ports on my NEW switch that my other boxes are attached to just fine.

I really don't know what else to try. I guess I've determined that I didn't screw anything up in the iptables while trying to configure the router.

The only thing else that I can think of that you should know is the computer is physically located in my basement by my utilities (water heater, air circulation unit, heater etc...) I can't believe that has an impact but the system was working when I had it upstairs so I just don't know what to do.

Does anyone have any ideas?!?!!?

I'll rerun the above commands and let you know if anything has changed since the first output.

Thanks for everyones help so far!

Noah

Ok... I've come to some kind of conclusion that my next step should be hardware diagnosis. Does anyone know of a hardware troubleshooting program that I could put on disk that will test out all of my components?

I don't know if there is something internal to linux that I can run or if I need to create a bootable cd.

Thanks for the help.

Noah Zenzen

Howzit

Try running a command called tcpdump and try capture this output to a file so that u can analyse later. You said that this machine is getting the IP via DHCP if this is thte case then there should be a entry or a request to the DHCO machine and a answer that will prove that the NIC is up and running. If nothing comes up then there is a problem with your machine.

What distro are u running?

Di u have other machines on your network and if so are they recieveing the IP from the modem/router

cheers

I will try that tcpdump and see what happens.

Here is what I have...

Red Hat Linux Enterprise server AS version 3

I was trying to set the server up either DHCP or STATIC. I would of course prefer static but right now I am just trying to get the thing on the network. I do have other machines on the network (all windows machines). The only other thing that I have on my network is a linux based wireless node to distribute a wireless signal. The other systems online are able to run either DHCP or Static but as of right now I turned the DHCP service off of my router/modem just in case that was doing something weird.

I will try and post the results of the tcpdump very soon.

Sorry it took me so long to post this. I just want everyone to know that I was able to fix the problem. What it boils down to was a compatibility issue between my cable modem/router device that was just installed an Red Hat Enterprise 3. I was able to down grade my Linux OS to Red Hat 7.3 and it popped online just fine.

Don't ask me why there is an issue with that modem/router but I guess I found out the hard way. My provider (comcast) never thought and right now still doesn't think (until I call them back) that there is an issue with that version of Linux. Unfortunately it also is the only modem/router they support for my service that I am getting.... so I am stuck. At least it works now.

Thanks for all the help everyone, I really appreciate it.

Noah Zenzen

Howzit

I saw that u where using a version of RH AS which ia server based OS which will have less compatibility for home use I thinkm it would a wise idea to change that version to WS which is more suited for a workstation or maby try dnld Fedora and replace the RH 7.3

Glad everthing is working

cheers

I appreciate the reply and idea. I have an issue with the software that I need to run on this box. First of all I didn't have a version of WS and I don't know if that would work because my guess is it had to do with the kernel version. The software that I need to run does work on Fedora 2 but the kernel still might be an issue and I am not impressed with the stability of FC2.

Thanks for all the help everyone!

Noah