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Tech

Howto:Change Server Shell Port

I saw this great post on SharkSpace by Amanda about how to change your server’s shell port. It said it was part of the dedicated server guide, but I thought it was good for people with VPSs (Virtual Private Servers) as well. Here’s the post:

1) Login to shell via root.

2) Open the shell configuration file.

nano -w /etc/ssh/sshd_config

 

3) Change port.

Uncomment and change

#Port 22

to look like:

Port 6472 (choose your own 2 to 5 digit port number (49151 is the highest port number)

 

4) Save and exit.

Ctrl + X + Y

 

5) Restart shell. (Make sure if you have a firewall installed that you have the new port unblocked.)

/etc/rc.d/init.d/sshd restart

Categories
Tech

Application Port Number

I was trying to connect to Google talk at work the other day via a third-party IM client called Miranda.  I downloaded a Google protocol (which actually runs on Jabber) but I couldn't get it to connect with the standard settings.  I figured it might be because my company has a firewall that blocks most ports, so I downloaded the official google talk client to see if it would work.

It went through a couple iterations of trying to connect to the server… and then… SUCCESS!  So why could it connect and my local client wouldn't?  As I assumed it was using a different port to connect.  Here's what I did to find out what port the application was running on.

I'll start with a high-level overview that power-users should be able to understand easily.  Then I'll break it down in a little more detail with the detailed steps needed to find out which port the application is running on.

High-level Overview: 

1. Open the Task Manager and find the PID for googletalk.exe 

2. Open the command prompt and run the " netstat -o -n" command

3. Find the PID in command prompt and find out which port it's running on. 

 

Detailed Steps

1. Press Ctl+Alt+Del to open the Task Manager (on some systems you may have to click the Task Manager button)

2.  In Task Manager, click View > Select Columns

3. Make sure the PID (Process Identifier) checkbox is checked and press OK

4.  Click the Processes tab, then scroll through the list and find the application you are looking for. Make note of the PID next to it.

5. Open command prompt: clcik Start > then click Run > type in "CMD" and press enter (a black command prompt should open)

6. Type in " netstat -o -n" and press enter*

*You can also add "-a" to the command to have it show more port information (all applications and listening ports)

7. Find the item in the list that has the same PID as you noted above. 

8. To find the port, look at the under the Foreign Address column and make note of the number after the colon.*

*This is typically called a socket and is in the format IP.add.re.ss:portNumber.  For Google talk this was 72.14.253.125:443 – meaning that the port number was 443 (which happens to be the default port for SSL connections).