Help answer threads with 0 replies.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 04-16-2009, 04:58 AM   #1
LQ Newbie
Registered: Apr 2007
Posts: 6

Rep: Reputation: 0
Can't communicate with servers on same subnet

The environment:

Two subnets: 192.168.0.x and 10.10.10.x. Servers are in 10.10.10.x.

Servers are Slackware of various releases.

Trying to add a new server. It is a replacement for an existing server so I have tried to set it up exactly like the existing server (except for the IP, of course.) All the servers have fixed IP's and are on the same hub. All the workstations have fixed IP's and are on the same hub.

These are the settings for the new server:

The gateway is

The hosts file:

# For loopbacking. localhost apache mail etrak_directory
# End of hosts.

The host.conf file:

order hosts, bind
multi on

The resolv.conf file:


One of the machines in 10.10.10.x is set up as a firewall and for port forwarding. The is on that machine.

Route appears to give the correct information:

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface * U 0 0 0 eth0
loopback * U 0 0 0 lo
default UG 1 0 0 eth0

although there is a significant delay (20-30 seconds) before 'default' is displayed.

I can:

- ping (the gateway) from the new server.
- ping all machines on the 192.168.0.x network from the new server.

I cannot:

- ping any machine (except the gateway) on the 10.10.10.x subnet from the new server but all the other servers can ping each other.
- ping the new server from any workstation (although this has worked from time to time and then just disappeared.)

arping quickly returns with 'Unicast...' and the correct hardware address but nothing else.

I have tested that it is a firewall issue by stopping the firewall... no difference.

Any ideas or pointers are appreciated.


Old 04-16-2009, 07:46 AM   #2
Registered: Dec 2008
Location: Newark Ohio
Distribution: Fedora Core
Posts: 270

Rep: Reputation: 37
On the machine setup as the firewall do you have both 192.168 and 10.10 on the interface that connects to the lan? When you say port forwarding I'd think you mean between the WAN and LAN network cards and really mean packet forwarding.

You could add a route to each machine to see the 192.168 network is local.

route add -net netmask eth0
Old 04-16-2009, 04:24 PM   #3
LQ Newbie
Registered: Apr 2007
Posts: 6

Original Poster
Rep: Reputation: 0

Thanks for the reply.

Yes, the firewall machine has three NIC's:, and 214.... (the Internet interface.)

I am less concerned about having the workstations be able to ping this server than I am about having this server be able to ping all the other servers (this one will be Tomcat and will need to communicate with the MySQL server on a separate box.) The puzzle for me is that all the servers (including this new one) are on the same subnet (10.10.10.x) yet this little bugger can't seem to ping the other servers.

Sometimes, I get the 'unreachable host' message but most of the time, ping just dies with no response (Example: ping from new machine usually just dies.)

Any other ideas?


Old 04-20-2009, 10:28 AM   #4
Registered: Dec 2008
Location: Newark Ohio
Distribution: Fedora Core
Posts: 270

Rep: Reputation: 37
Please paste the output of route -n and ifconfig


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
OpenVPN-client connects,cant see servers subnet andbn Linux - Networking 0 10-29-2007 12:24 PM
Get an IP, but still can't communicate with network... bthornton Linux - Networking 21 03-21-2005 07:16 AM
nslookup returns local ip when resolving another servers fqdn on same subnet nodrogx Linux - Networking 3 10-28-2003 02:12 PM
communicate via serial... how-to? adam_boz Linux - Newbie 4 10-22-2002 10:30 AM
Can IP from different subnet be configured on another subnet russell Linux - Networking 1 08-23-2002 01:47 AM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 12:46 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration