Cisco IOS: It's Not Just for Routing Anymore | Page 1

NEWS BLOGS FORUMS NEWSLETTERS RESEARCH EVENTS DIGITAL LIBRARY CAREERS

IMMERSE YOURSELF:

Storage & Servers

Cisco IOS: It's Not Just for Routing Anymore
May 31, 1999

Additional Information

Related Links

Network Computing, Feb. 22, 1999
"The Cost of Security on Cisco Routers"

Network Computing, Feb. 8, 1999
"Cisco 1720 Ensures Secure Links"

Network Computing, April 15, 1998
"Demystifying Cisco Access Control Lists"

Company Directory

Browse our directory to get data, starting with a particular company.

Reader Service

Allows you to request additional product information from our advertisers.

Print The Full Article

Click

Here

E-mail this URL

Click

Here

Buy the Book

By Greg Shipley Cisco Systems' Internetwork Operating System (IOS), the software that runs on the vendor's routers, has become the network administrator's Swiss Army knife. We found that IOS version 12, the most recent revision, continues to improve upon fundamental routing principles and is chock-full of new features--NAT (Network Address Translation) support and expanded ACL (access control list) and VPN functionality, for starters--that go beyond basic routing. Knowing how to leverage these features can save an administrator much time and effort.

On the security front, IOS has supported ACLs for IP, SAP, IPX and other protocols. Version 12 adds NAT, which had been available only in traditional firewall products; it lets administrators map internal/hidden IP addresses to external/public ones. This functionality is useful to organizations using RFC1918-based addressing, as well as those needing quick fixes for address-duplication conflicts between remote sites. With NAT, administrators have the choice to hide an entire network behind a single address/interface. Known as IP masquerading--or PAT (Port Address Translation) in Cisco-speak--this technique is helpful to remote offices that use an ISDN connection for inexpensive Internet access.

We configured a Cisco 3640 router running IOS 12 for NAT (also available in some builds of the IOS version 11.x firewall edition) with little difficulty. First, we simply defined our NAT table within the global configuration mode:

ip nat inside source list 1 interface Serial1 overload

access-list 1 permit 10.9.100.0 0.0.0.255

We then defined the NAT table within the interfaces of the internal and external networks:

interface Ethernet0/0

ip address 10.9.100.254 255.255.255.0

ip nat inside

interface Serial1/0

ip nat outside

The above configuration lets any host on the Ethernet segment 10.9.100.0/24 masquerade as the serial interface's IP address. In this case, we configured the serial port for dial-on-demand routing, and we were able to "hide" an entire RFC1918-based, Class C address range behind a dynamically assigned PPP address (see "Using NAT," to the right).

Page 1 | 2 | 3 | Next Page

Ready to take that job and shove it?
Open | Close

Post Your Resume

Employers Area

News & Features

Blogs & Forums

Career Resources

Browse By:
State | City

SPONSOR

RECENT JOB POSTINGS

Featured Jobs:

Boeing seeking Software Engineer 5 in Anaheim, CA

KForce seeking Inside Sales Associate in San Diego, CA

Amalgamated Bank seeking Chief Information Officer in New York, NY

Apollo College seeking Medical Billing and Coding Instructors in Albuquerque, NM

Allstate seeking Exlusive Agent in Las Vegas, NV

For more great jobs, career-related news, features and services, please visit our Career Center.

CAREER NEWS

Federal CTO Sees IT Leading U.S. Out Of Recession

Aneesh Chopra is looking to other CIOs to advise him on fleshing out a more detailed agenda to best serve the president's IT agenda.

IT Spending To Fall By 3.8 Percent

IT spending is expected to decline by 3.8 percent in 2009 according to Gartner.

More articles from our career center


Today's Most Popular Stories • Rolling Review: SOA Appliances • Making The Move To Multicore • Rolling Review: Web 2.0 Tools Demand A Cautious Approach • Rolling Review: Windows Server 2008 Server Core
Today's News Analysis • Amazon EC2 Entices Innovative Uses With Persistent Storage • AIG Private Client Group Diagnoses SOA Glitches With BMC Solution • CA Emphasizes Holistic Enterprise IT Management • Apple Previews Its Next Mac OS 'Snow Leopard'
REPORTS Analyize In-Line NAC strategies and products.	ANALYTICS Plan and design your enterprise blade server deployments

2009 IT Salary Survey: Meager Raises, Solid Prospects

Though raises are notably smaller than a year ago, and job security�s shrinking, IT careers are looking safer than many others in this economic downturn. Get all the findings in InformationWeek's 2009 IT Salary Survey. Available FREE for a limited time.