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Old 01-10-2013, 01:42 PM   #1
kaempfer0080
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Registered: Jan 2013
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Can ping server, can't SSH. No internet access.


Unfortunately this is going to be quite complicated due to the nature of the network and my inexperience, but I'll try to explain the setup as best I can.

We have 2 networks here at a small business. One is the local network I set up over the summer, which has a domain controller and some hard drives. No complaints there.

Recently we moved all the servers from our other location to this building. They were all hooked up to a VPN so the employees over seas could access certain servers. I was able to get the VPN up and running and can remote into all the servers ocne logged into the VPN, with the exception of the file server. We use a Cisco rv082 small business VPN router.

The server in question is the only linux machine on the network, I believe it's a Dell Poweredge 410 running Fedora 14. It has 2 network adapters which, under the old configuration, were both plugged into the VPN router. I checked on the router and found they had the same IP address(x.x.67.25) and though an IP conflict might be the culprit, but disabling either adapter had no results. I never set up anything on the server but it had been up and running at the previous location. It's basically just a large data server with some samba shares set up. I guess one strange thing I should mention is that after moving the server no one could log in, I had to boot up in single user mode and change all the passwords. Still no idea why, could be a sign of corruption?

I'm able to ping the linux server from the other machines on the VPN, and any other machine if I log in to the VPN(we use Cisco Quick VPN). The linux server has never had internet access since we moved it, but I'm able to log in to the router. I can also ping the other machines on the VPN from the linux server. A friend of mine suggested trying to SSH as troubleshooting, so I gave that a shot but had some problems. The server does have an ssh daemon running and I am able to ssh locally, eg ssh user@localhost works fine. I figured this was a port forwarding issue so I forwarded port 22 to the IP of the linux server, but no result there.

The linux server also has the same gateway as the other machines that have internet access and are available for remote access.

EDIT: Forgot another thing I had tried. I hooked the linux server up to our local network to see if I had internet access, could SSH, etc. I still couldn't connect to the internet but was able to ping and SSH into the server from a machine on the local network. When I tried to map the drive it seemed like my connection attempt or credentials were being rejected. I put //x.x.67.25/shares into the network path and it asked me to login, but the login window just kept closing and reprompting me over and over. No error message was given. I may have tried a few other network paths.

Still no internet access though which I thought was strange.

Please let me know what other information you might need. Unfortunately I'm new to linux and networking in general so this has been quite a task for me.

Last edited by kaempfer0080; 01-10-2013 at 01:45 PM.
 
Old 01-11-2013, 09:06 AM   #2
kenneth_phough
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Location: Birmingham, AL
Distribution: CentOS, REHL, Vine Linux
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I was able to follow until I got to your edit. So I am just going to repeat what you said briefly (correct me if I am wrong): You brought a linux file server from your old location to the new which has two networks. When connected to network 1 the linux box had ssh, file sharing, internet connectivity problems, including authentication problems. You moved the server to the other network and now you can ssh but no internet connection.

First it would help to know how the interface is configured. If you are unsure what the interface is do
Code:
ifconfig
and find the interface names, usually eth0, eth1, etc... If at this point you see a interface named bond0, bond1, etc... that means the two nics are bonded, which can be seen on server for either failover or bandwidth purposes.

Next could you tell me how that interface is configured?
For example for interface eth0:
Code:
more /etc/sysconfig/network-scripts/ifcfg-eth0
Is it DHCP, or static? Is there a gateway set? etc...

Next, does the file server use a directory server to authenticate users?
Check /etc/nsswitch.conf to see if there is the word ldap
If so that may explain the login/authentication problem.

Once we have this info, we can look at the firewall next.

Last edited by kenneth_phough; 01-11-2013 at 09:07 AM.
 
Old 01-11-2013, 12:40 PM   #3
kaempfer0080
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Quote:
Originally Posted by kenneth_phough View Post
I was able to follow until I got to your edit. So I am just going to repeat what you said briefly (correct me if I am wrong): You brought a linux file server from your old location to the new which has two networks. When connected to network 1 the linux box had ssh, file sharing, internet connectivity problems, including authentication problems. You moved the server to the other network and now you can ssh but no internet connection.
Yes, that's correct.

Quote:
Originally Posted by kenneth_phough View Post
First it would help to know how the interface is configured. If you are unsure what the interface is do
Code:
ifconfig
and find the interface names, usually eth0, eth1, etc... If at this point you see a interface named bond0, bond1, etc... that means the two nics are bonded, which can be seen on server for either failover or bandwidth purposes.
Ah okay, I was wondering why the 2 adapters were plugged into the same router. They are indeed bonded, eth0 and eth1.

Next could you tell me how that interface is configured?
For example for interface eth0:
Code:
more /etc/sysconfig/network-scripts/ifcfg-eth0
I think I screwed something up while trying to troubleshoot, probably when I switched the networks and had to change the static IP settings. There was no ifcfg-bond0 file so I rewrote one. It looks like this now:

Code:
DEVICE=bond0
IPADDR=10.226.67.25 (static address of the machine)
NETWORK=10.226.67.1 (address of the VPN router, the gateway)
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
BONDING_OPTS= mode=6 miimon=100
ONBOOT=yes
TYPE=Ethernet
PREFIX=24
GATEWAY=10.226.67.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System bond0"
UUID= <Long string, is it relevent?>
Everything below ONBOOT=yes was generated automatically by something, I'm assuming from when I looked through the connection in edit connections.

I also wrote the eth0 and eth1 cfg files as follows:

Code:
DEVICE=eth<0/1>
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
There is a file in /etc/modprobe.d/bonding.conf
Code:
alias bond0 bonding
I ran # cat /proc/net/bonding/bond0 and got:

Code:
Bonding mode: load balancing (round-robin)
MII Status: up
MII Polling Interval(ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: x.x.x.x.c3

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: x.x.x.x.c4

Quote:
Originally Posted by kenneth_phough View Post
Is it DHCP, or static? Is there a gateway set? etc...
The VPN router does DHCP, the file server's IP is x.x.67.25. The gateway is the IP of the VPN router, x.x.67.1.


Quote:
Originally Posted by kenneth_phough View Post
Next, does the file server use a directory server to authenticate users?
Check /etc/nsswitch.conf to see if there is the word ldap
If so that may explain the login/authentication problem.

Once we have this info, we can look at the firewall next.
I didn't find ldap in this file.


I'm not sure I set up the bond correctly, when I run # service network restart I get

Code:
Shutting down interface bond0: Error: Device "bond0" not found [FAILED]
It looks like eth0 and eth1 reboot okay, but after restarting eth1 isn't connected to system bond0.
 
Old 01-15-2013, 07:50 AM   #4
kenneth_phough
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Registered: Dec 2005
Location: Birmingham, AL
Distribution: CentOS, REHL, Vine Linux
Posts: 67

Rep: Reputation: 3
You need double quotes around your bonding options otherwise each will be parsed as an interface config (also start with the minimum needed confs - it's easier to trace the problem that way ).
Code:
DEVICE=bond0
IPADDR=123.456.789.2
NETWORK=123.456.789.1
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
BONDING_OPTS="mode=6 miimon=100"
ONBOOT=yes
GATEWAY=10.226.67.1
IPV6INIT=no
I usually like to declare my bonding options in modprobe.d/bonding like so:
Code:
options bond0 mode=balance-alb miimon=100
# balance-alb is mode 6
Let me know how it goes.
 
  


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