Troubleshooting Network connectivity

Host A is trying to connect to Host B but is unsuccessful.

Host A is trying to connect to Server but is unsuccessful.

Troubleshoot:

1.   Check Host A's network configuration:
           # ifconfig -a
              Is the IP address OK ?
              Is the Gateway address correct ?
              Has the Netmask been set correctly ?
              Is the MTU setting OK ?

2.  Check the /etc/sysconfig/network file:
              Is the Gateway address entered correct ?
              Is the Hostname showing correctly ?

3.  Check the /etc/sysconfig/network-scripts/ifcfg-eth0 entries:
               IP address for the eth0 interface
               Gateway address
               Is the BOOTPROTOCOL set to "static" ?
               Broadcast address
               Netmask information

4.  Run the # ethtool eth0     command and check if the "Link Detected" shows Yes.

5.  Check the Cisco Layer 2 switch for:
              Is the # switchport mode access         set correctly ?
                       # switchport access vlan <VLAN-ID>
              Is the VLAN information correct ?
              Does the # show mac address-table           show the MAC address of the Host A on the                         connected Port

6.   Routers:
              Check for the Routing table entries:        # show ip route

That should do.