Stupid question about ports on the back of a 2600

Answered Question
Sep 22nd, 2010

I am a student and just started cisco learning. I have a Cisco 2600. I have already configured the router using HyperTerminal. There are four ports on the back of the router (FastEthernet 0/0, FastEthernet 0/1, console, and aux). The lab book I followed said to configure FastEthernet 0/0, but it does not say anything about what ports to plug into what after that. My question is what port should I use to connect it to the modem, and what port should I plug in the workstation?? No where in my CCENT book, my lab book, or text book for class does it say what ports are used for what. Thank you very much in advance.

Correct Answer by mrmoothe about 6 years 5 months ago

Hi,

I'm glad you've found a document... just let us know if you need anything else...

In the meantime, let me try and summarize a couple of things...

modem ---- (Fa0/0) Router (Fa0/1) ------ Desktop

We need a few things for the desktop to be able to go out into the internet.

Link 1 (Desktop to Router)

1. Desktop should have an ip address.

2. The interface Fa0/1 should have an ip address in the same range as the desktop.

3. If you do a ipconfig on the desktop - you should see it pointing to the ip address of fa0/1

Now you should be able to ping Fa0/1 from the desktop

Link 2 (Router to Modem)

1. Fa0/0 should have an ip address

This generally would be provided by the modem. Try using the command 'ip address dhcp' under fa0/0 and you should get an ip address.

2. A default route from the router towards the modem

Now this could happen in many ways and you'll have to try a couple of things based on the modem.

The modem might be pushing a default route to you in which case...

     ip route 0.0.0.0 0.0.0.0 fa0/0 dhcp

Should give you a default route.

To check whether you have a default route on a router - do a 'show ip route 0.0.0.0' and check whether you have an entry.

If the above does not give you a default route - also try reloading the modem... this generally helps.

Link 1 + Link 2

By now... you should be able to ping the router from desktop (ip address on fa0/1) and ping the internet from the router over the modem (say ping 4.2.2.2)

For traffic to go from the desktop to the PC we might need to do some NATting... but before we get there... get link 1 and two up and running...

Let me know if you have any issues.


Cheers

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mrmoothe Wed, 09/22/2010 - 08:04

Hi Sky,

First of all no question is a stupid question... 

Let's see here...

The following is a link regarding cabling on cisco devices. It should help you get started and understand Console and AUX ports better...

http://www.cisco.com/en/US/products/hw/routers/ps332/products_tech_note09186a0080094ce6.shtml

But for normal access... plug in your modem and your workstation both to the fast ethernet ports.

If you can give me more detail on what you're trying to achieve... I could help you probe this futher.

Cheers!

MRM

sky.oneil Wed, 09/22/2010 - 08:31

@ Manas R Moothedath,

I am just trying to connect the router to my home network and be able to get internet to one workstation.

So It just goes Modem to Cisco 2600 to Windows desktop.

If you know, could you explain in student terms lol. ex. modem > straight cable > Fastethernet 0/0. Fastethernet 0/1 > crossover cable > desktop.

Spent four hours researching last night for this question and was starting to get mad. Your help is greatly appreciated!

Thank you for the link, I am reviewing it now.

Correct Answer
mrmoothe Wed, 09/22/2010 - 14:05

Hi,

I'm glad you've found a document... just let us know if you need anything else...

In the meantime, let me try and summarize a couple of things...

modem ---- (Fa0/0) Router (Fa0/1) ------ Desktop

We need a few things for the desktop to be able to go out into the internet.

Link 1 (Desktop to Router)

1. Desktop should have an ip address.

2. The interface Fa0/1 should have an ip address in the same range as the desktop.

3. If you do a ipconfig on the desktop - you should see it pointing to the ip address of fa0/1

Now you should be able to ping Fa0/1 from the desktop

Link 2 (Router to Modem)

1. Fa0/0 should have an ip address

This generally would be provided by the modem. Try using the command 'ip address dhcp' under fa0/0 and you should get an ip address.

2. A default route from the router towards the modem

Now this could happen in many ways and you'll have to try a couple of things based on the modem.

The modem might be pushing a default route to you in which case...

     ip route 0.0.0.0 0.0.0.0 fa0/0 dhcp

Should give you a default route.

To check whether you have a default route on a router - do a 'show ip route 0.0.0.0' and check whether you have an entry.

If the above does not give you a default route - also try reloading the modem... this generally helps.

Link 1 + Link 2

By now... you should be able to ping the router from desktop (ip address on fa0/1) and ping the internet from the router over the modem (say ping 4.2.2.2)

For traffic to go from the desktop to the PC we might need to do some NATting... but before we get there... get link 1 and two up and running...

Let me know if you have any issues.


Cheers

sky.oneil Wed, 09/22/2010 - 14:27

Great info. You just solved my headache. Thank you very much once agin!

NickNac79 Wed, 09/22/2010 - 08:08

Hi Sky,

Your FastEhernet (Fa0/0 and Fa0/1) are for connecting to other Ethernet devices, like other routers, switch and PCs etc.

The console port is used for when you configure the device through a serial port (e.g. using Hyperterminal)

The AUX port, is kind of 'another' console port, that is used for several things - one of the main ones is for connecting DIRECTLY to an old Serial Dialup modem, e.g. a 56.6Kbps Modem.

This is used for you to Dial into the device remotely (say if you've installed it into somewhere that's 200 Miles away, and you need to configure it but have no Network connection)

Another use is for a reverse telnet connection, but at this point that's a bit beyond what you need to know.

For now, ignore the Aux port.

Hope that helps, and Good Luck ;-)

Nick

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