Linux box on a Windows domain ran network, can't get the dang thing on the internet.

abcde597 · 06-21-2013, 07:09 PM

I can get it hooked up and all but I can't get the dang thing on the internet.
My school just allowed personally owned devices, and of course, everything except the printers run Windows...
And so, being different, I decide to introduce *Nix to the "Virgin" network.
I hook it up, and I can access all devices on the network, but I can't connect to the internet. Any ideas?
(Sorry about how stupid I may sound, I'm tired.)

frankbell · 06-21-2013, 09:06 PM

What distro/version of Linux? Does your schools policy ban non-Windows devices?

It might help get things started if you post the output of ifconfig (you may have to run it as root, depending on the distro), being sure to surround it with "code" tags, which become available when you click the "Go Advanced" button at the bottom of the quick reply window.

Also, try pinging devices within the network. If the ping is successful, try pinging outside the network (ping google.com, for example) and seeing what happens. If the internal ping succeeds and the external fails, try a traceroute [somewhere] outside; that could indicate the location of the failure.

If the ping is not successful, you likely aren't getting out of your box, but be aware that ICMP settings in some devices prohibit them from returning pings.

lleb · 06-22-2013, 12:52 PM

in addition to what frankbell stated also using code flags post your /etc/resolv.conf, it should look something like the following:

Code:

[user@server ~]$ cat /etc/resolv.conf 
nameserver 192.168.222.111

this is were your DNS is stored in Linux, well at least the RedHat flavors (fedora and the like) I think it is the same for Debian based as well like Ubuntu and Mint.

MikeDeltaBrown · 06-23-2013, 04:36 AM

Are you using DHCP to setup your networking or did you assign an IP address statically?

In addition to the listing of /etc/resolv.conf, can you post the output of `ifconfig` and `route -n` ?

abcde597 · 08-26-2013, 08:23 PM

Sorry it's taking so long guys...
Had to talk to IT guys.
Yeah, it's fine, I was told not to expect support for any issues.
They love me

I'm using a Debian fork.
I CAN ping devices on the network and get replies, I just can't leave the network.
As for the tracert...
I forgot

Here's the output of ifconfig.

Code:

eth2      Link encap:Ethernet  HWaddr 88:51:fb:80:07:92  
          inet addr:172.20.3.118  Bcast:172.20.255.255
	  Mask:255.255.0.0
          inet6 addr: fe80::8a51:fbff:fe80:792/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3583 errors:0 dropped:0 overruns:0 frame:0
          TX packets:116 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:352025 (343.7 KiB)  TX bytes:10452 (10.2 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:10 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:620 (620.0 B)  TX bytes:620 (620.0 B)

I'm using DHCP to setup my networking.

MikeDeltaBrown · 08-28-2013, 02:20 PM

...and then we need the output of `route -n`. To get packets to leave the local network, the computer needs to know the "gateway" address. That should be setup via DHCP, but we should check.
Something like:

Code:

Host# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
[snip]
0.0.0.0         172.20.0.1      0.0.0.0         UG    204    0        0 eth0

If you don't have a default route entry you'll need to ask your IT friends what it is (or see below). You can add it temporarily with:

Code:

route add default gw 172.20.0.1

If there is a default route entry, try to ping an outside IP address:

Code:

ping 173.194.34.177

If that works you have a working gateway and default route.
Then try to ping www.google.com to test name resolution. Per LLEB's post, the file that controls name resolution is /etc/resolv.conf. You can get the information you need to populate the file from a Windows machine by running `ipconfig /all` from a DOS window and finding the configured interface. The Connection-specific DNS Suffix value will go into the 'search' line (ie. LAN). The DNS Servers value(s) will go into the 'nameserver' line(s). If your IT friends weren't any help with the gateway address, you can get it from the 'Default Gateway' line.
A good /etc/resolv.conf would look like:

Code:

search  LAN
nameserver 172.20.x.x
nameserver 172.20.y.y