The Case of the New Cable/DSL Modem
In these lean times, people shop for less expensive connectivity choices, but business networks aren’t as simple as home networks. Changing Internet Service Providers (ISPs) can cause connectivity issues on a business network if the new modem isn’t configured properly. Even without changing ISPs, similar problems can arise when replacing your router or even just a wireless access point. To help explain the issue, the following article is reprinted from a technical bulletin distributed by Comsift.
At least once a week Comsift Support receives a service call where the customer’s Internet Service Provider (ISP) has replaced the customer’s cable/DSL modem and nothing works; or the customer has switched ISPs, received a new cable/DSL modem, and nothing works.
Typically, the customer asks, “How do I reconfigure the ComSifter so everything works?” If only it was that easy.
The Case of Default Settings, or “How can I get out of here fast?”
Usually, the ISP’s technician comes in with the new modem, replaces the old modem, connects his laptop to the new modem, adjusts some settings, and then shows the customer how fast the new Internet connection works. Everyone smiles, the technician packs up his gear and leaves.
Then you discover-nothing works.
What the technician did was install the new cable/DSL modem with factory default settings. Normally, these setting will be something like 192.168.0.1 or 192.168.1.1 and the modem’s DHCP server is turned on. This works great in a home environment, where only a few computers are connected. Everyone is happy, and the consumer does not even realize that his or her network settings have changed.
However, what about your school environment, the new modem is set to 192.168.1.1 and DHCP is turned on. Your existing network was 192.168.0.1 and you have a ComSifter, a Domain Controller, four network printers, five access points and a network copier-and now nothing works.
WHAT TO DO
You could spend the next few days reconfiguring you network to the new settings-calling your vendors to help you re-configure all your network devices-or you could be prepared when the ISP’s technician walks in the door.
Have all of the network devices documented. Know who is doing DHCP on your network. Explain to the technician that YOU want the new modem to be set to the same settings as your existing network. Guess what-it will only take the technician 10 minutes to setup the new modem. When done, your new modem will match your existing network-not the other way around (i.e. your network matching the new modem).
As you can imagine, an extra 10 minutes of the technician’s time will save you hours and maybe days of reconfiguring your network.
What changes, if any, will need to be made on the ComSifter? Typically, only the DNS settings will change if you have switched ISPs. You will need to go into the Network Wizard and change the DNS settings to match your servers new ISPs DNS server’s. If the ComSifter is also performing DHCP server functions, you may need to change the DHCP Client Options to reflect the new DNS settings.
A few minutes of preparation and requiring your technician to adjust to your network may make you smile.
If you need to replace a cable modem or router, Maverick Solutions would be happy to handle the project for you. If you’d rather do it yourself, we can help you create the network map and configuration documentation that the article suggests. It’s really a good piece of documentation for every network owner to have on hand.
Comsift, Inc. is one of Maverick Solutions’ preferred vendors for Internet Content Filtering (ICF) solutions. We’d be happy to help you select and deploy one of their appliances (and we often can arrange discounted pricing), or if you prefer to contact them directly, please let them know we referred you.
We also wrote an article specifically about Internet Content Filtering.
