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Old 12-05-2004, 03:57 PM   #1
djljjm
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Network Issues


Ok I am really confused now...

My net went down about a week ago for no apparent reason. I am using Fedora Core 3 and the internet worked fine for about 3 weeks then just stopped. I assumed that my hardware had failure...then this morning I decided to test a few things out...

I am on a T1 university line and decided to try my roomates IP address...to my surprise it worked! But of course....it booted my roomie from his connection saying that someone had taken his IP address...then to the next step. I deleted that connection and made a new one...this time making it automatically get an IP (I had tried this quite a few times)...it didn't work...the school says to set up windows by doing the "auto" setting for everything, there is no static IP provided. Before my net went down this was the setting it was on. What am I supposed to do?

It is detecting the DNS and on bootup there is a bit of a lag on Eth0 but it does say OK...then on time synchronization it said "failed"

Thank you!
djljjm
 
Old 12-05-2004, 04:08 PM   #2
sigsegv
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Sounds like fedora doesn't like your uni's DHCP server. Do a service network restart and tail the messages log. That should give you some ideas where to look.

Also, do an ifconfig -a and see if you're really getting an address or not. If you are, then it's something else. netstat -rn would be good too, to see your routing table.

Last edited by sigsegv; 12-05-2004 at 04:09 PM.
 
Old 12-05-2004, 05:16 PM   #3
djljjm
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Not sure what all of that means

Thanks for the advice....I need some info on what a lot of that stuff means (I'm a newbie). What is "tail the message log" what am I looking for and how do I look? How do I see if I am getting an address or not with ifconfig -a ? and what am I doing with netstat -rn?

Thanks!
djljjm
 
Old 12-05-2004, 05:37 PM   #4
sigsegv
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tail the messages log means to tail /var/log/messages. ifconfig -a gives you the current interface settings for all the interfaces on the system. You should see "inet xxx.xxx.xxx.xxx" in whicch the xxx.xxx.xxx.xxx will be your IP (If any). netstat -rn will show you your routing table.
 
Old 12-05-2004, 07:10 PM   #5
djljjm
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Update :(

I ran the service network restart and everything went through fine...a bit of lag on the Eth0 but I think that's normal. Then I did the ifconfig -a and wasn't sure what to look for but there was definitely an IP. Then I ran the netstat -rn and this is what came up

Destination Gateway Genmask Flags MSS Window
xxx.xxx.xx.x 0.0.0.0 xxx.xxx.xxx.x U 0 0
xxx.xxx.x.x 0.0.0.0 xxx.xxx.xxx.x U 0 0
0.0.0.0 xxx.xxx.xx.x 0.0.0.0 UG 0 0

x=a number

so I did have IP's come up and other numbers...what do I do with them...or what do they mean? Thanks a lot for walking me through this.


djljjm
 
Old 12-05-2004, 08:08 PM   #6
sigsegv
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... With no IPs, it's kinda hard to tell you anything useful.

Are you able to ping the IP in this line of output from netstat? 0.0.0.0 xxx.xxx.xx.x 0.0.0.0 UG 0 0 If you are, you have the basic things that you need for networking. Try to ping your roomie's IP.
 
Old 12-05-2004, 08:52 PM   #7
djljjm
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Details

the netstat -rn says this...

Destination
128.195.91.0
169.254.0.0
0.0.0.0

Gateway
0.0.0.0
0.0.0.0
128.195.91.1

Genmask
255.255.255.0
255.255.255.0
0.0.0.0

Flags
U
U
UG

MSS
0
0
0

Window
0
0
0

Iface
Eth0
Eth0
Eth0

Those are all lines up...just a pain to do it in the box...

I pinged my roomate and it gave me something like this
his ip (his ip) 56(84) bytes of data

then it just acted as if there was a lock (the markee kept blinking but it never said #root...)again...I just closed the command box
 
Old 12-05-2004, 09:35 PM   #8
sigsegv
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Ok, so can you ping 128.195.91.1?
 
Old 12-05-2004, 09:43 PM   #9
djljjm
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Ping

From my computer or from another computer? I just pinged it from my friends computer and it worked.

Thanks a lot!
 
Old 12-05-2004, 09:58 PM   #10
sigsegv
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From yours. If your computer won't ping it's default gateway, that would do it.

Also, does your roomie's computer live on the same subnet? Are the first three octets of his IP the same as yours, and does he have the same netmask?
 
Old 12-05-2004, 10:25 PM   #11
djljjm
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Ping

I can ping myself but it does the following

64 bytes from (address): icmp_seq=XXX ttl=255 time = (ms)

and the xxx just keeps going up by 1...it is at 158 right now.

My roomates IP begins with the same first 3 octets and the same mask (I think the entire hall has the same one)

djljjm--Joel
 
Old 12-05-2004, 10:39 PM   #12
djljjm
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More....

Well now I tried to put in my roomies IP again and the net won't work...not sure how I got it to work the first time and not sure if this info is necessary but thought I would put it down. Thanks
 
Old 12-05-2004, 11:08 PM   #13
sigsegv
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Well, it sounds like you're basically down to one of two things. Either your nic/cable has gone bad (you can ping yourself but can't ping anywhere else it seems), or you've botched something up bigtime in a firewall script or something else that would be causing your packets to be falling into the bit bucket ...

Can you ping your IP from your roomie's computer? If not, try booting your computer up on a "run from CD" distro (Knoppix or Mepis or something) and see if the network is available that way.

If it is, your install is hosed, most likely in the firewall.
 
Old 12-06-2004, 12:13 AM   #14
djljjm
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More....

I already tried Knoppix and it didn't work...I also pinged myself from my roomates computer and it did work.

I would think that I didn't botch anything since my computer worked with my roomates IP address in it...that seems like there isn't a major problem...maybe I'm wrong.

djljjm
 
Old 12-06-2004, 07:35 AM   #15
sigsegv
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Re: More....

Quote:
Originally posted by djljjm
Well now I tried to put in my roomies IP again and the net won't work...not sure how I got it to work the first time and not sure if this info is necessary but thought I would put it down. Thanks
It doesn't work with his IP or a knoppix CD ... I think it's time to suspect hardware. Try swapping your patch cable with his. If that doesn't work, do you have another NIC?
 
  


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