Network Problems between servers(can't communicate)

[Greg Hale]

We have 2 HP servers, a K570 running 10.20 and a N4000-36 running 11.00. Both are hooked up to our network. The problem is that we cannot communciate between the two servers. Cannot ping,telnet, traceroute, etc... between the 2 servers.

Can ping, telnet, traceroute, etc...from my PC to these servers.

I had the Network Control Center take a look and they see no problems with the routers or switches. They can ping both servers from the routers/switches.

We can ping other servers from both of the servers, as well.

When I do a traceroute from the N class to the K class it gets as far as the K class' router. when I do a traceroute from the K class to the N class it shows no results at all.

Was given the following notes:

Verified connectivity in both directions from Ethernet interface 0/0/3 and Fast Ethernet interface 0/1/0. Able to perform extended pings from the destination router interfaces to the Servers. Examined log file for discrepencies related to these two interfaces and there were none. Issue is not network related.

Checked access-list to see if blocking ping from ethernet segements, currently no access-group is assigned on interfaces.

What else can I check to see why these two servers cannot communicate with each other while at the same time they can communcate with other servers and other servers/pcs can communicate with them.

thanks,

Greg

[Rick Garland]

Do some checks on the network equipment. Are the systems in the same subnet or different subnets? If different subnets, can the packets be routed over the different subnets? Is there a firewall or something to that effect in place?

[Medavie]

Greg if both servers are on the same network segment verify that the nic card is setup with the correct speed and negotiation. One could be 100FD and on 10HD and with auto negotiation on the switch should see them but the would not talk together. Set them to what your network group says they have to be set at.

[Alan Riggs]

Have you verified the basics: name resolution and netmasks on each server? Have you tested connectivity to other devices on the same subnet(s)?

[Rita C Workman]

If communication is only an issue between these two...Have checked and see if in inetd.sec you have denied access somehow?

It sounds (since you say you can access these boxes from other servers...) like some kind of network security type issue...Rick's suggestion is something I'd check first..

/rcw

[Peggy Fong]

Hi
Out of my league here, but does linkloop work between the two servers (assuming they are on the same subnet).

Good Luck.
Peggy

[Brian Hackley]

Greg,
Just a quick guess that this appears to be a routing issue at first blush. The K traceroute to the N hits the router, and the N can't even get to the router when it tries to traceroute? Check the routing on the N-class with netstat -rn and debug from there. I suspect that is the cause. Good luck!
Brian Hackley

[John Bolene]

Check the default gateways on both machines since it sounds like they are in different segments.
Machines on the same segment can talk if the gateway is not setup for routing packets to other segments.

[Kevin Wright]

since your going over the router, these boxes (I assume) are on different subnets..you need to add the network to the other box in the route table,
route add -net xxx.xxx. gw (your router) eth0
and be sure to add the hop count at the end
see man route

[Jaimin Parikh]

Hi Greg,

I think you should check your gateway,routers/firewall config which are used in inter-connecting these two servers.

Try connecting both the servers on same device / segment temporarily for testing and then check the communication between those two servers.

This is more like a routing related issue.

REgards,
Jaimin.