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Cisco Professionals eTips
| One way to load router memory from a remote server
If you need disaster recovery on your router memory (e.g., the router flash card failed and you've had to replace it), loading your Cisco IOS software image onto the new memory can be difficult without the appropriate tools.
One approach is to load the software image from a TFTP server using the tpdnld command. This command is reserved for disaster recovery as it may erase all of the data on your flash memory.
There are a number of steps required in using this command. The following gui shows an example of how to do it:
www.cisco.com/en/US/docs/routers/access/1800/1841/software
/configuration/guide/b_rommon.html#wp1070700
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Abolish bogus bounces with BATV
While users may be marginally annoyed by the bogus bounces known as backscatter, these false bounce notifications can seriously disrupt an email server. Spam with forged "From" addresses containing your domain may cause you to receive so many spurious bounce messages that they may overload the server, similarly to a denial-of-service attack.
One solution is to use a special code in the return address that allows the server to tell if a bounce message really corresponds to an email that was sent from your domain. Bogus bounce messages are rejected. The standard implementation of this strategy is known as Bounce Address Tag Validation (BATV), which was defined in the Internet Draft.
BATV works by appending into the return address a timestamp and cryptographic token. This is known as "tagging." A typical return address using BATV looks like this:
prvs=[some code]=[email address]
Cisco IronPort email security appliances implement this approach using a feature called IronPort Bounce Verification.
BATV can have some potential drawbacks. Users may be confused by the strange return address. Mailing list managers and systems for greylisting and spam-filtering may not properly recognize the altered return address. In addition, some systems may send bounce messages based on something other than the return address, so BATV may not eliminate all backscatter.
You can configure IronPort Bounce Verification so it exempts certain domains. This may be helpful if there's a domain to which you frequently send emails where tagging is known to cause problems.
If using Cisco IronPort AsyncOS 7.1 or a similar version, you can find out more about how to configure IronPort Bounce Verification on page 2-127 at the following address:
www.cisco.com/en/US/docs/security/esa/esa7.1/adv_config_guide
/ESA_7.1.1_Advanced_Configuration_Guide.pdf |
| Power interactive screens in a centralized way
Large screen displays and interactive kiosks are useful tools for providing customers with the information they need when they're in public areas, such as malls, airports, etc. Such tools are can also be very useful from a marketing perspective.
If you want to set up this kind of equipment, it's useful to have a centralized system, so you can manage each screen and kiosk in a uniform way. Cisco's Interactive Services Solution is one option to power this kind of infrastructure. The Interactive Experience Manager allows you to configure and manage your various screens and kiosks, which each constitute an Interactive Experience Endpoint powered by an Interactive Experience Client. Each screen or kiosk can access the Web and can integrate with a number of peripherals, such as cameras, speakers, and headsets.
To find out more about Interactive Services, go to the following web page:
www.cisco.com/en/US/prod/collateral/video/ps9339/ps12435
/brochure_c02-701258_ps12434_Products_Brochure.html
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| How taking inventory of your network can save energy and money
While taking inventory of your network can help you keep track of the organization's equipment, it's also a good way to lower energy bills. For example, it's important to know if there's any duplication of network resources; an analysis of how computer equipment is being used can help spot such inefficiencies.
It's not uncommon in some organizations for departments to add some of their own equipment or even install a network by themselves. While this may not seem a problem if they're able to be self-sufficient, it may lead to excess power use if it duplicates other equipment or isn't implemented in the most efficient way. Similarly, the many rapid organizational changes common in business these days mean that there may be a lot of equipment that's no longer needed.
Even needed equipment that's functioning properly may be wasting energy if it doesn't have the latest power-saving features. In some cases, replacing equipment may save money in the long run. For these reasons, taking inventory of your equipment and making the necessary adjustments is a great way to reduce your power use.
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A simple reset when ASDM fails
As often happens with computers, if you're not able to manage ASA through ASDM, and everything seems to be set up properly, sometimes simply resetting the connection fixes the problem.
To connect to ASA through ASDM, you must enable ASA's HTTP Server, which allows for remote management through HTTPS. So, if there's a mysterious problem connecting from ASDM, try disabling and re-enabling the HTTP Server:
no http server enable
http server enable
Of course, also check that you've specified the correct hosts to have access to ASA.
For other ASDM troubleshooting procedures, consult the following web page:
www.cisco.com/en/US/products/ps6121/products_tech_note09186a0080aaeff5.shtml |
A Facebook for business
Perhaps you've wished your company could have something like Facebook - a more natural way than email to communicate and share information between employees. Cisco has created such "enterprise social software", called Cisco Quad. It's a platform for inter-employee communication, very similar to the Facebook interface, but more catered to the controlled and full-featured environment needed in a workplace setting. You can think of it as an intranet Facebook, geared toward work-related posts.
One of the ideas behind such software is that newer employees are so used to Facebook and other social networking software that they'll prefer workplaces that employ similar interfaces for corporate communications. Compared to email, social networking interfaces may be a more intuitive way to share information with groups of people. It can also make it easy for employees to locate whom to contact for various needs. Unlike with organization charts or directories, it's likely that profiles will be kept up-to-date if employees have a sense of ownership over their own profiles and can easily edit them. Comprehensive collaboration software can also remove the need to develop various in-house solutions for sharing information with and between employees.
Cisco Quad may be a good choice for organizations that use Cisco hardware and seek a social networking interface that may better cater to younger employees compared to some other collaboration options.
To find out more about Cisco Quad, go to www.cisco.com/go/quad.
Of course, Cisco Quad isn't the only product in the enterprise social software space, and some competitor products are more widely known. Other software packages to consider include Microsoft SharePoint, IBM Lotus Connections, and MindTouch (which started out as free open-source software, but now follows a commercial cloud-based model). |
| Avoid this common mistake in your ASA configuration
The wrong lines left in your ASA configuration can easily create security holes. It's interesting how frequently one hears of ASA configurations with lines like this:
http 0.0.0.0 0.0.0.0 outside
This gives every IP address full access to the ASA device from the outside interface. Unfortunately, sometimes such lines are left in because someone was debugging a problem such as trying to see why nobody can access the network from outside. To ensure that these lines haven't been accidentally left in your configuration, run the "show running-config" command.
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Ways to set the VLAN for non-Cisco VoIP phones
If you plug non-Cisco phones into your Cisco-based network with multiple VLANs, you may have trouble assigning the correct VLANs to the phones, unless you use the appropriate protocol.
Cisco uses the proprietary The Cisco Discovery Protocol (CDP) to share data between equipment at the data link layer. However, even though this protocol is proprietary, some non-Cisco equipment are licensed to use it.
If a phone doesn't support CDP, it may support the more standard Link Layer Discovery Protocol (LLDP). So it's useful to check if the phone supports LLDP, which you can use to assign the VLAN. Cisco's "switchport voice" command works for configuring the VLAN on phones that support CDP or LLDP.
If a phone supports neither, usually there's still a way to assign the VLAN. Typically, you can do this by setting custom DHCP options. This is generally better than the remaining option of setting the VLAN manually on each handset. |
Convert the dreaded voicemail to text with SpeechView
Voicemail has become one of the necessary evils of modern office life. When that light flashes on your phone, indicating that there's some voicemail, you have no idea what it's about and how long you'll have to spend listening to the message to find out. Unfortunately, often when people leave voice mail, it's for an urgent matter.
Cisco SpeechView (part of Cisco Unity Connection) converts voicemail to text messages, so employees can easily scan their voicemail and not have to be bothered listening to each individual message.
In our experience, SpeechView is surprisingly accurate in converting text ... far more reliable than, say, dictating into an iPad.
You can find out more about SpeechView at the www.cisco.com/go/SpeechView. |
| A simple small business solution for easy networking without rewiring
If you're running a small business on a tight budget, one new tool at your disposal is the ability to extend the network with standard electrical wiring. This approach eliminates the need to run new cables throughout the building and gives you speeds up to 200 Mbps. You can also use this technique to extend your wireless network to different areas of the building and eliminate dead spots.
To accomplish this, Cisco offers kits to plug the network into regular AC sockets called HomePlug AV Powerline solutions. Although designed for home use, this product, which you can buy for around $100, could also be used as a simple networking tool for a startup business.
You can find out more at the following location:
http://homestore.cisco.com/en-us/products
/linksys-powerline_stcVVcatId554690VVviewcat.htm
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| A softer reboot
Sometimes, resetting the network may be necessary to diagnose or resolve a problem. However, there are options that will cause less of an interruption than, say, rebooting the ASA.
For example, the "clear local-host" command releases all connections. This kills all current packet streams going through ASA. However, in most cases, the devices will just retry the packets once the network is back up. So while this is a powerful command that you wouldn't want to issue unnecessarily, it can be slightly less disrupting than a full reboot.
You can also specify a specific IP address after "clear local-host" to limit its effect.
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| Stay green (and legal) by eCycling
When network and computer equipment are no longer serviceable or reusable and aren't eligible for Cisco's trade-in program, it's important to dispose of them properly. Not only is proper recycling better for the environment, but improper disposal of equipment risks violating the law.
Sometimes it can be confusing where to turn to dispose of old equipment. Fortunately, Cisco offers a Takeback and Recycle program to take this equipment off your hands. To get more information on this program, go to the following website, click the map to specify your location, and select your country at the bottom of the page:
www.cisco.com/web/about/ac227/ac228/ac231/WEEE/index.html
You may wonder about other alternatives, especially for non-Cisco equipment. In the U.S., the EPA lists resources for where you can recycle your old electronic equipment. Use the following links:
www.epa.gov/osw/conserve/materials/ecycling/donate.htm
www.epa.gov/osw/conserve/materials/ecycling/live.htm
www.epa.gov/osw/conserve/materials/ecycling/
For information about laws in your area regarding recycling electronics equipment, the following web page is helpful:
www.electronicsrecycling.org/public/ContentPage.aspx?pageid=14
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