Networking

Access the Cisco CLI with one of these five terminal emulators

The best way to manage the Cisco IOS is through a terminal emulator using the command-line interface (CLI). What's the best terminal emulator to use? David Davis asked TechRepublic members, and he's got five options for you to choose from.

In a recent article, I discussed creating a definitive list of Cisco management tools that should be in every administrator's toolbox, and I asked for TechRepublic members' help ("What's the best Cisco router configuration and management tool?"). Many of you chimed in with valuable suggestions. I've taken notes on all of the recommended products, and I'll be writing articles to introduce you to some of the lesser known -- but very valuable -- Cisco network management tools.

This time, I want to focus on a core tool that many members mentioned they had to have -- a terminal emulator. It might not be the most glamorous area of networking tools, but it's an essential tool that you must have to use the Cisco IOS command-line interface (CLI).

The best way to manage the Cisco IOS is through a terminal emulator using the CLI. You can use a terminal emulator to connect to a router, switch, or firewall's CLI interface either over the network using Telnet or SSH protocols or over a serial line connected to the console of the device.

Members didn't disappoint with their recommendations for a terminal emulator. Here's a quick look at their suggestions. Let's find out how the terminal emulators recommended by readers compare.

SecureCRT

A product of VanDyke Software, SecureCRT provides Telnet, serial, and SSH for the Windows OS. It offers a script recorder, logging, and multiple session windows.

SecureCRT integrates with SecureFX for file transfer, and it only works on Windows. I have seen SecureCRT used at Cisco sites and on Cisco testing computers. It's been around for a while (current version is 5.5), and Cisco fully supports it.

One copy costs $99 (U.S.). Figure A shows a screenshot of SecureCRT.

Figure A

SecureCRT

PuTTY

An implementation of Telnet and SSH for Windows and UNIX platforms, PuTTY provides Telnet, serial, and SSH. It features a single executable to run and no installation. It supports logging, and source code is freely available. One downside is that the connection list isn't easily stored.

Currently in version .60, PuTTY hasn't seen heavy development, but it works great. Also available are PuTTYtel, PSCP, PSFTP, Plink, Pageant, and PuTTYgen, as well as hundreds of other products based on the source code of PuTTY.

Best of all, PuTTY is free. Figure B and Figure C show screenshots of the tool.

Figure B

PuTTY

Figure C

PuTTY

TeraTerm Pro

Available from Ayera Technologies' Web site, TeraTerm Pro provides Telnet, serial, and SSH for the Windows OS. It supports logging, and the source code is freely available. It offers a saved setup, as well as add-ons such as a macros editor.

Overall, this is a very nice terminal emulator. It's similar in look and feel to SecureCRT.

TeraTerm Pro is free. Figure D shows a screenshot of the tool.

Figure D

TeraTerm Pro

Windows telnet

Supported by the Windows OS, the telnet command provides Telnet only. It's only available at the Windows command prompt, and odds are good you're already familiar with this option.

Its biggest advantage is that it's free. Figure E offers a screenshot of using this option.

Figure E

Windows telnet command

Windows HyperTerminal

Also included in the Windows OS, the Windows HyperTerminal program provides Telnet and serial, but no SSH. It offers logging and XMODEM file transfer to get files onto switches or routers with the correct IOS.

While Windows HyperTerminal is also free, it can be frustrating to use sometimes. Figure F offers a screenshot of the program.

Figure F

Windows HyperTerminal

Of course, there are many more Windows terminal emulators than just these -- including PowerVT, PowerTerm, WRQ Reflection, HotVT, TinyTERM, and BlueZone. For Linux, there are even more (such as Konsole).

Summary

There are some great terminal emulators out there available for no cost. In my opinion, it's worth the time to upgrade from Windows HyperTerminal or the telnet command -- neither one of these options will likely do the job for you in the long run.

While PuTTY is great, TeraTerm Pro seems even more full-featured. And if you have some budget money to spend, SecureCRT is by far the best product.

One thing about terminal emulators is that no matter what network you work on or what type of Cisco network equipment you have, you have to have a terminal emulator -- and you have to know how to use it.

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David Davis has worked in the IT industry for 12 years and holds several certifications, including CCIE, MCSE+I, CISSP, CCNA, CCDA, and CCNP. He currently manages a group of systems/network administrators for a privately owned retail company and performs networking/systems consulting on a part-time basis.

13 comments
mike.christenson
mike.christenson

You need to make sure when you write an article that you include the feature set required. To enable ssh you have to have the security feature set. We only have it on our public router that is exposed to the internet. Naturally, that was the first router I tried to enable ssh on and everything worked fine. Then I pulled my hair out trying to enable it on the internal routers until I discovered none of them have the security feature set required.

vbb1964
vbb1964

I work on Cisco, Juniper, Tellabs, Nortel, and just about every other type of network routers, DXCs, switches, and transmission equipment. I created the fastest, most reliable, and secure terminal emulator out there. This was designed to allow you to do your job fast and efficently without mistakes. It records, reports, and automates many functions especially with Cisco based service provider mpls VPNs. It works without a install and can run off a USB key so bring it with you and use it on any Windows based PC. Check it out www.rampart-ssh.com for more details. This is free and always will be. SecureCRT would be my second choice from your list but why pay $99.

djdawson
djdawson

Konsole does not appear to support access to serial ports. I'd be interested in knowing what emulator people use with Linux other than "minicom". On BSD systems I'm happy with "tip", but that doesn't seem to be a normal part of the few Linux distributions I've looked at (Ubuntu and Debian).

mark
mark

I would try ZOC. I've been using it for a while and it works great. The clipboard is a lot more functional and it remembers connection settings.

bart.thoen
bart.thoen

He, that's new !! PuTTY suporting serial connections ! Since what version? The version i'm using doesn't (v 0.53b). Anyway , it's nice to know that it does. I'm upgrading my PuTTY as soon as i can. My preffered terminal emulator is SecureCRT. (unleash the function keys !! ;-). Very handy when you want to loging very fast (and perform some predefined commands up front)

djdawson
djdawson

SSH *is* supported in all Feature sets in the recent 12.4 releases, so it's not as simple any more to just reference a particular IOS feature set. To determine exactly what software you need for a particular feature in Cisco IOS, I suggest using their Feature Navigator: http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp

mercedesman1981
mercedesman1981

I found TeraTerm in its older versions to not have much reliability when it came to posting large configuration changes, ie, anything more than 10 or 15 lines of an ACL, to a device. I switched to Secure CRT and have not looked back. I especially like the ability to change screen colors to differentiate connections to devices (red for firewalls, green for switches, etc).

chasbrey
chasbrey

I really dig this .60 version of PuTTY! Telnet and serial console through a single, easy-to-use interface. It's clean and unpretentious. I modified the default settings for a much larger window (100 char x 60 lines) to see more of the config at once. It became a necessity since my recent testing upgrade to Vista Business revealed no integrated terminal emulation. Yes, telnet and hyperterm are gone...or at least I haven't the time or inclination to hunt them down. For mass deployment of configuration changes I fronted the cash for Solarwinds Engineers Edition. I can push a single config change to any individual or group of monitored devices. I can group them by location, model, IOS version or whatever other other criteria is dictated. I sure do love SNMP.

mike.christenson
mike.christenson

I thought it was obvious in my post - we don't have an IOS version that has the feature set required to enable ssh and the IOS CD that came with the router doesn't have the required version either. That's why it's important to note which IOS version and feature set is required when publishing an article. Several articles have been published that require a particular feature set that we don't have. I'm sure there are others reading these articles that have run into the same problem. The URL you provided is very nice for finding IOS versions that contain various feature sets, but what good does that do me when I don't have the IOS version required and am not interested in purchasing it?

A50MHzHam
A50MHzHam

The article mentions that the connection list isn't easily stored using PuTTY. What does that mean? Is that a reference to the lack of a simple way to export a list of sessions to a portable format? That's something we do all the time, share a list of sessions (connections) with new employees to get them up to speed. It's not hard to do-- it's all stored in a registry key. Usually it's in HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions It's not hard to export the sessions key (and all below it) to a REG file and pass that along. Double-click it and allow import and there you go.

mike.christenson
mike.christenson

Again, the navigator is a nice tool, thank you for the URL. Trying to figure out all the various Cisco feature sets and IOS versions is quite daunting. The ability to search for specific features in the navigator will make it much easier. I inherited an old system, and the city is not willing to spend any money to upgrade hardware or software, or purchase a support agreement.

djdawson
djdawson

It would be nice if all the articles referenced the appropriate IOS version and feature set, but in the absence of that information I thought people might find the Cisco Feature Navigator useful, since you can determine *exactly* what software supports what features. You can even use the "Search by Image" link to get a list of all the features supported by your particular router software. If you did that once for each of the different versions of IOS you're running, you'd have a handy reference for future articles that don't happen to list IOS versions and/or feature sets. That's why I thought the link I provided would be useful to you. Since Cisco has so many different versions of hardware and software products, it's not really feasible for every article to list all the platforms and software versions a given feature will work with. If you've used the Feature Navigator then you've seen the vast range of platforms and features involved. Perhaps this would be a good topic for an article by Mr. Davis, if he hasn't already done it (hint, hint).