I believe that after eliminating the possibilities of problems at the previous steps, the only remaining option at this step is to troubleshoot the application. You may need to scrounge through log files, check application consoles, etc.
However, the possibility of a problem occurring due to the underlying network is extremely minimal at this level - even if it does, it's probably due to some idiosyncrasies of the Operating System or the Application Platform.
Showing posts with label Network. Show all posts
Showing posts with label Network. Show all posts
Monday, February 25, 2008
Network Troubleshooting - 5 : NETSTAT
You need to now move on to the Remote System & check if the program / process is listening on a particular port that you are trying to connect to.
Netstat (network statistics) is a command-line tool that displays network connections (both incoming and outgoing), routing tables, and a number of network interface statistics.
- Wikipedia
You can use the simple NETSTAT command on the remote system to check the open Network ports, active connections, etc . You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
( LINUX )
netstat -an | grep port_name
OR
( WINDOWS )
netstat -an | findstr port_name
You should see a bunch of Network statistics like this :-
TCP 0.0.0.0:1521 0.0.0.0:0 LISTENING
TCP 127.30.22.11:1521 10.177.239.210:2527 ESTABLISHED
TCP 127.30.22.11:25271 10.177.239.210:1521 ESTABLISHED
TCP 127.30.22.110:28802 10.177.145.53:1521 ESTABLISHED
If you don't get this response, you can conclude on these :-
1. The program / process on the remote system that should be "listening" on the port is not running.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Netstat (network statistics) is a command-line tool that displays network connections (both incoming and outgoing), routing tables, and a number of network interface statistics.
- Wikipedia
You can use the simple NETSTAT command on the remote system to check the open Network ports, active connections, etc . You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
( LINUX )
netstat -an | grep port_name
OR
( WINDOWS )
netstat -an | findstr port_name
You should see a bunch of Network statistics like this :-
TCP 0.0.0.0:1521 0.0.0.0:0 LISTENING
TCP 127.30.22.11:1521 10.177.239.210:2527 ESTABLISHED
TCP 127.30.22.11:25271 10.177.239.210:1521 ESTABLISHED
TCP 127.30.22.110:28802 10.177.145.53:1521 ESTABLISHED
If you don't get this response, you can conclude on these :-
1. The program / process on the remote system that should be "listening" on the port is not running.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Network Troubleshooting - 4 : TELNET
A TCP/IP standard for remote terminal connection to another machine.
- Wikipedia
You can use the simple TELNET command to ensure that you can communicate with the remote system, by opening a connection to a port on the remote system. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
telnet ip_address port
OR
telnet hostname port
You should see a blank screen that allows you to type commands.
If you don't get this response, you can conclude on these :-
1. The program / process on the remote system that should be "listening" on the port is not running.
2. The remote system is protected by a "firewall" that's preventing access.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
- Wikipedia
You can use the simple TELNET command to ensure that you can communicate with the remote system, by opening a connection to a port on the remote system. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
telnet ip_address port
OR
telnet hostname port
You should see a blank screen that allows you to type commands.
If you don't get this response, you can conclude on these :-
1. The program / process on the remote system that should be "listening" on the port is not running.
2. The remote system is protected by a "firewall" that's preventing access.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Network Troubleshooting - 3 : PING
Ping!
Ping is a computer network tool used to test whether a particular host is reachable across an IP network.
- Wikipedia
You can use the simple PING command to ensure that you can communicate with the other system. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
ping ip_address
OR
ping hostname
You should see a reply from the Network Card like this :-
Pinging sandeep-personal [127.0.0.1] with 32 bytes of data:
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
If you don't get this response, you can conclude on these :-
1. Your system is not connected to the same network as the remote system.
2. The remote system is not connected to the same network as your system.
3. Your system / the remote system is protected by a "firewall" that's preventing access.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Ping is a computer network tool used to test whether a particular host is reachable across an IP network.
- Wikipedia
You can use the simple PING command to ensure that you can communicate with the other system. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
ping ip_address
OR
ping hostname
You should see a reply from the Network Card like this :-
Pinging sandeep-personal [127.0.0.1] with 32 bytes of data:
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
Reply from 127.30.22.11: bytes=32 time 1ms TTL=128
If you don't get this response, you can conclude on these :-
1. Your system is not connected to the same network as the remote system.
2. The remote system is not connected to the same network as your system.
3. Your system / the remote system is protected by a "firewall" that's preventing access.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with Network Access.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Monday, January 28, 2008
Network Troubleshooting - 2 : Check the Adapters
Check the Network Card.
A network card, network adapter, LAN Adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network.
A network card, network adapter, LAN Adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network.
A Network card allows you to send / receive messages to / from other computers in the same Network. Hence, the next obvious checkpoint is the Network Card.
You can use the simple PING command to ensure that the Network Card is working as expected. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
You can use the simple PING command to ensure that the Network Card is working as expected. You just need to open a Command Prompt ( Terminal in LINUX ) & type :-
ping localhost
You should see a reply from the Network Card like this :-
Pinging sandeep-personal [127.0.0.1] with 32 bytes of data:
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
If you don't get this response, you can conclude on these :-
1. The Network Card is not properly installed.
2. The Network Card is not properly configured.
3. The Network Card is no longer functional.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with the Network Card.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
You should see a reply from the Network Card like this :-
Pinging sandeep-personal [127.0.0.1] with 32 bytes of data:
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
Reply from 127.0.0.1: bytes=32 time 1ms TTL=128
If you don't get this response, you can conclude on these :-
1. The Network Card is not properly installed.
2. The Network Card is not properly configured.
3. The Network Card is no longer functional.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with the Network Card.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Friday, January 25, 2008
Network Troubleshooting - 1 : Check the Cables
Check the Cables !
Yes, the most simplest method is toe check if Network Cable is properly connected to the computer.
Here's a small Checklist that I use :-
* The Network Cable is connected correctly to the Network Card (usually, rear of the Computer)
* The Network LEDs are flashing green - continuous or blinking.
If any of the above are not correct, I am sure there's something wrong with connection. If the Cable is connected correctly & your computer is still unable to get on the Network, you might want to try with a new Network Cable.
If it works - you have solved the problem :)
If you don't get this response, you can conclude on these :-
1. The Network Card is not able to get a signal from the Network.
2. The Network Card is not properly installed.
3. The Network Card is not properly configured.
4. The Network Card is no longer functional.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with the Network Card.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Yes, the most simplest method is toe check if Network Cable is properly connected to the computer.
Here's a small Checklist that I use :-
* The Network Cable is connected correctly to the Network Card (usually, rear of the Computer)
* The Network LEDs are flashing green - continuous or blinking.
If any of the above are not correct, I am sure there's something wrong with connection. If the Cable is connected correctly & your computer is still unable to get on the Network, you might want to try with a new Network Cable.
If it works - you have solved the problem :)
If you don't get this response, you can conclude on these :-
1. The Network Card is not able to get a signal from the Network.
2. The Network Card is not properly installed.
3. The Network Card is not properly configured.
4. The Network Card is no longer functional.
Now, it's time to call up the IT Help Desk & tell them that there's a problem with the Network Card.
At the end of this exercise, you have :-
* tried some basic troubleshooting steps.
* identified the source of the problem.
* communicated effectively to the IT Support Staff.
You can now confidently communicate with the IT Support Staff & they'd be more than happy to work with an "educated" colleague.
Network Troubleshooting - 0 : Need
A fairly good understanding of Networking concepts is important if your are working on a Multi-Tiered Distributed Project.
You could be working on JEE or any other Technology stack - without a basic understanding of he underlying network, you will frequently find yourself wondering why some of the components "don't talk to each other".
You need to have a basic understanding of the underlying Network, a few common problems & simple troubleshooting. It will help you articulate the nature of the problem to your Stakeholders & most importantly to your IT Help Desk Staff.
I also ask a few networking questions during my interview sessions to gauge if the candiate if aware of some of the basic facts.
I am definitely not an expert in Networking, but I would like to share some observations from my limited experience.
You could be working on JEE or any other Technology stack - without a basic understanding of he underlying network, you will frequently find yourself wondering why some of the components "don't talk to each other".
You need to have a basic understanding of the underlying Network, a few common problems & simple troubleshooting. It will help you articulate the nature of the problem to your Stakeholders & most importantly to your IT Help Desk Staff.
I also ask a few networking questions during my interview sessions to gauge if the candiate if aware of some of the basic facts.
I am definitely not an expert in Networking, but I would like to share some observations from my limited experience.
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