Network Connectivity troubleshooting

This tutorial explains the steps to follow for basic network connectivity troubleshooting

Do I know this quiz

1.What should be the default gateway IP address configured on a PC which needs to communicate with a system on the same network.
2.Name one reason as to why a ping response is not received from a system on the network.

In this tutorial, we understand the steps which can be used to troubleshoot basic connectivity issues to systems which are residing on the same and different network.

Step 1

Check the physical connectivity of PC1 with switch. This can be verified using the appropriate light on the switch and the network card.

Step 2

Check if the IP address and subnet mask of PC1 and PC2 is configured properly on the TCP/IP adapter of PC1 using ipconfig command (Windows) and ifconfig (Linux). Sometimes , the subnet mask would be configured incorrectly.

Step 3

Ping the IP address of PC2 from PC1. If a reply is not received, check if ARP resolution is working using protocol analyser like wireshark. Check if PC1 is sending an ARP request and an appropriate ARP reply is being send back by PC2. Check if a desktop firewall on PC2 is blocking the ping requests.

Steps 1 -3 can be used to troubleshooting connectivity problems with systems on the same network.

Step 4 is used to test connectivity between systems on different networks. Step s 1-3 are common techniques which can be used for both scenarios

Step 4

Check if the TCP/IP adapter of PC1 and PC2 is configured with the appropriate default gateway IP address, which is 192.168.1.1 and 192.168.2.1 Ping the IP address 192.168.1.1 from PC1 and 192.168.2.1 from PC2. This would verify connectivity to the default gateway from the respective PC’s

Step 5

Check ping connectivity to the IP address 192.1682.1 from PC1 and 192.168.1.1 from PC2. This is to verify connectivity between networks. If a ping reply is not received, check the routing table of the router and verify if the routes corresponding to the networks, 192.168.1.0/24 and 192.168.2.0/24 is available.

Answers to the Do I know this quiz

1.The default gateway should be the IP address of the router, which is aware of the remote networks and resides on the same network. For, ex, the default gateway IP address of PC1 should be 192.168.1.1.
2.The remote system would have a software firewall which would be blocking the ping response from the system.