HWIC/WIC to turn 1841 into a true router?

Answered Question
Jul 31st, 2008

I was recently hired by my current company and my boss told me to look into turning our 1841 into a router. Currently, only 1 slot is occupied with a WIC-1DSU-T1. Our PIX 501 firewall currently handles our routing functions.

Can anyone point me into the direction of a WIC or HWIC that we can put into the other slot and let the 1841 handle the routing so the PIX doesn't have too?

I have this problem too.
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nappyjim9 Thu, 07/31/2008 - 12:49

Hi Jim,

Sorry, routers are not my strong point...I am more of a server guy.

Anyway, we have our T1 coming into the 1841 and then the PIX firewall is connected to one of the Ethernet ports on the 1841. Attached is a diagram. (showing only what you need to see)

Basically, what he told me was, the 1841 is currently acting as a CSU/DSU but he wants it to be a router as well. He wants to implement VLANS.

Attachment: 

No worries. Thanks for the info. Here are my thoughts.

The diagram shows basically what you are describing. Your 1841 is acting as an edge router. Have you considered dropping the Cisco PIX 501 out of your network and having the 1841 pick up its firewalling responsibilities? What other roles besides firewall is the PIX currently handling? VPN? I ask because with the appropriate IOS feature set the 1841 can easily do all of these jobs depending on traffic loads and such. The problem with having the 1841 be both an edge and internal router and keeping the PIX is that you would need to have the traffic routed twice. Once as outside traffic before the firewall and once again after the firewall has processed it. Rolling all of the functions into one device simplifies this. If you are unfamiliar with Cisco CLI I suggest checking out Cisco SDM as it has some very well designed GUI driven wizards to help you with all of this.

nappyjim9 Thu, 07/31/2008 - 13:05

Yes, the PIX is acting as a firewall and VPN.

So you think the 1841 could handle all of that? We have a small network ~35 users.

nappyjim9 Thu, 07/31/2008 - 13:12

I am running IOS version 12.4. Not sure how to check the feature set.

nappyjim9 Thu, 07/31/2008 - 13:18

Cisco IOS Software, 1841 Software (C1841-IPBASE-M), Version 12.4(1c), RELEASE SO

FTWARE (fc1)

cisfajorin Mon, 08/04/2008 - 08:24

what you need is a total reorganisation of your network architecture,I will not really say you should get rid of the router,since you already have it. i will suggest u harden the router by disabling exploitable features and maximize the resources on the pics,ur vpn and basic firewall features. the advantage of doing this is basically to protect ur investments. for the new T1 line all u need is just a hwic that supports T1 eg the VWIC-1MFT-T1 and some other available ones,check cisco http://www.cisco.com/en/US/prod/collateral/routers/ps5853/product_data_sheet0900aecd8016a59b.html

jfchang72 Fri, 08/01/2008 - 00:41

I try to configure my CISCO 1841 router. Attached is my configuration. I try to enable load balancing for FE0 & FE1 but somehow won't works. Can anyone help me out?

jfchang72 Mon, 08/04/2008 - 00:36

Hi,

I try to add in some of the command from the link that you provided but somehow my not working properly. Please refer my configuration attached. It always route thru the Fix IP port and with the DHCP on, it give timeout...

Hello,

The link I provided was just a configuration example. You would need to tweak it to fit what you have. In the example they had one interface with a static IP and the other acquired via DHCP. From your initial config I see you are static on both. In this case, you will just need to re-apply your static IP to the FastEthernet0/1 interface. The naming on the route-maps is purely for identification purposes so don't worry about that. Also, you may look at using routing to an IP address instead of just out the interface if this doesn't do what you need.

Jim

jfchang72 Wed, 08/06/2008 - 17:40

Hi Jim,

Where can I find a suitable IOS for my CISCO 1841 Router? Following is my existing IOS.

Cisco IOS Software, 1841 Software (C1841-IPBASE-M), Version 12.4(1c), RELEASE SO

FTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Tue 25-Oct-05 17:10 by evmiller

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

FABER uptime is 1 minute

System returned to ROM by power-on

System image file is "flash:c1841-ipbase-mz.124-1c.bin"

Thanks.

Chang

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