Server Red Hat and error message Destination Host Unreachable

[zillah]

The Linux server Red Hat that I have got at my lab is giving me this error :

((Destination Host Unreachable.....))


Its NIC is up, and IP, Subnet Mask, Default Gateway is fine, the Cisco switch where it connected is configured correctly, but neither any one can ping this Red Hat Server nor it can ping any one on the same network.

Switch shows green light , that means physical connection (NIC, cable) should be ok.

If I unplugged the server and plugged my laptop instead, they can ping each other (switch and other PCs and laptop)

I even added the default router under the properties of NIC on Red
Hat Server....it didn't make any difference.

1- Beside the firewall (enabling and disabling) that I have to check



2- Can I uninstall TCP/IP and reinstall it again (If that feasible like windows)?

[mechdave]

Have a look at /etc/hosts file, make sure that the line

127.0.0.1 localhost.localdomain localhost

is present along with your FQDN. The other file I often have trouble with is the /etc/resolv.conf. Make sure the ip address of your DNS servers (primary and secondary) are present
Hope this helps

[peter]

Can you ping your default gateway? Is the subnet mask on both machines the same or correct? Does the DHCP information the laptop receive the same as that configured on the server (except the gateway information)?

[zillah]

The Linux server Red Hat that I have got at my lab

IP are static addresses that means I have not used DHCP.

Is the subnet mask on both machines the same or correct

If I unplugged the server and plugged my laptop instead, they can ping each other (switch and other PCs and laptop)

I have used same ip address for the server and laptop.

[peter]

Do you see any mac addresses associated with the interface? If not you could have a bad cable or NIC card.

What does your tcpdump output look like when you attempt the ping? If you see traffic in only one direction, that could provide a clue.

[peter]

Typos in subnet masks can be tricky.

Two hosts.

a) 192.168.1.1 255.255.255.0
b) 192.168.1.16 255.255.255.240

(A) will think that (B) is on the same network, but (B) won't think that (A) is on its network.

Can you ping the default gateway?