Dec
07
2008
Written by: Craig Haynie

It is quite annoying to have to walk to the server room with a laptop and console cable in hand every time you need to make a change to your router, switch, firewall, or other network device’s configuration. Fortunately there are some easier and better ways.

There are two main ways to accomplish this task. One is very easy and very cheap but provides limited flexibility. If you only need to control one device or mainly control one device and occasionally one or two others this may be a good solution. If you truly want to never leave your desk again or if you have several devices you may opt for the second option.

Option 1: Run a cable using existing wiring

I have been in my new building for over a year and it just now occured to me that I could do this. It’s quite simple and works well and as long as you have an extra network drop at your workstation (an unused network port that is wired back to your patch panel in your server room) you are in business!

Find the port on your patch panel that is connected to the unused port at your workstation. Connect that port to your Cisco device using a standard Cat5e or Cat6 patch cable. Go to your workstation and connect the RJ45 end of the console cable to the network jack you chose earlier. Connect the other end of the cable (the DB9 end) to your workstation. If your workstation does not have a DB9 port you can use a USB to DB9 adapter. Open your favorite terminal client such as HyperTerminal and enjoy!

As I mentioned above, this option has limitations. You obviously are only connected to one device so when you want to control a new device you need to walk to the server room and move the cable. Depending on how often you need to make changes to more than one device this may not be practical. If that is the case the second option may be for you.

Option 2: Using a terminal server

This is easier than it sounds, although it does require spending a little money. Using a Cisco 2509 or 2511 Router and one or two CAB-OCTAL-ASYNC cables you can easily connect to 8 or 16 devices and console to them remotely using telnet. You can actually connect to non Cisco devices as well by using a coupler and a specially made cable for each type of equipment but we will only discuss connecting to Cisco devices in this article. Also, other Cisco devices can be used for this purpose as well but we are only going to talk about the 2509/2511 in this article.

Very similar to option 1 (using existing wiring), this option simply extends your reach by putting a rubber band so to speak between you and your Cisco device(s). It’s not complicated so don’t overthink it. Buy you a Cisco 2509 or 2511 router and one or two CAB-OCTAL-ASYNC cables (2509 uses one, 2511 can use one or two). Install the router into your rack and get it powered on. Configure it as follows:

Router>enable

Router#configure terminal

Router(config)#interface loopback0

Router(config-if)#ip address 10.20.10.50 255.255.255.255
(Use whatever IP is available on your network)

<CTRL>Z to get back to get out of the interface config.

Router(config)#ip host hostname1 2001 10.20.10.50

Router(config)#ip host hostname2 2002 10.20.10.50

“ip host” is the command

“hostname1″ or “hostname2″ can be anything you want. This can be the actual hostname of the unit you are connecting to if there is one or you can just use “router” or “switch” or “hostname1″, “hostname2″ or whatever. This doesnt “do” anything, it would only be useful if you were going to initiate a terminal session to the device from within the 2509/2511 (if you logged into the router FIRST before connecting to the device). I will explain the easy way to connect to devices without first connecting to the router shortly.

2001, 2002, 2003, and so on refers to the physical port on the router. The octal cable has a 68 pin male connector on one end that you will connect to a female async port on the router. The other end of the cable has 8 RJ45 connectors that you will connect to your devices, each of which are labeled 1 though 8. So on a 2509 if you connected the cable with a 1 on it to your device you would use 2001, if you used the cable with a 7 on it you would use 2007, etc. A 2511 has two ASYNC ports so if you connect a second OCTAL cable to the unit you need to translate a little. RJ45 cable number 1 (on OCTAL cable number 2) would be port number 9 and so on (since the first cable is already connected to ports 1-8)

10.20.10.50 is the IP address of the 2509/2511. Dont over think this, this is the way it is supposed to be. What this does is sends anyone trying to connect to port 20XX on that unit to iteslf! (Since itself is where the cables are connected)

So lets say you are going to use a 2509 and therefore a single CAB-OCTAL-ASYNC cable. Lets say you give the unit an IP address of 192.168.1.10 and have one router (called DALLAS-2610) connected to the RJ45 cable marked 5 on the OCTAL cable. You would use the IP address 192.168.1.10 when configuring the router and when adding the host you would use:

Router(config)#ip host DALLAS-2610 2005 192.168.1.10

Once you are done with the configuration you connect to DALLAS-2610 by going to a command prompt on your workstation or your favorite telnet software. If using a command prompt you would type:

telnet 192.168.1.10 2005

That should connect you directly to your 2610 called DALLAS-2610!

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