5 Quick Wlan Config Tips

5 Quick WLAN Config Tips

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5 Quick WLAN Config Tips
Ben Miller, Global Knowledge Course Director November 2009 I fly around the country frequently and meet a lot of people who use Wi-Fi. The consensus, I find, is that it's a great technology with a few things that are frustrating. Sometimes it goes out, sometimes it gets slow, the security is opaque, etc. The good news is thatthe positives outweigh the negatives (otherwise people wouldn't use it, right?). The bad news is that direct information on simple config changes that might improve things can be hard to find. So in an effort to do my part to better humanity (or at least humanity's ability to have Internet access from their sofa), here are five quick config tips that might improve things. Tip #1: Choose yourchannels. No need to rehash what everybody knows about channels 1, 6 and 11. (And if you don't know, just trust me and stick to those channels only.) With this tip I'm talking about two lesser-known things; namely, the flaws in automatic channel selection and the ability to choose your band on some notebooks. When configuring a large infrastructure of controller-managed APs, it's tempting to use theautomatic channel selection function. Don't. At least, don't if you need top performance. Auto-channel selection is great for quick configs of basic Wi-Fi (like for guests, consultants, web access, etc.), but it almost never works as well as planning your channels manually. If you leave auto-channel select running, you'll almost certainly end up with adjacent APs on the same channel and lots ofinterference from power outputs left too high. On stations, channel selection is quite different. You don't choose your channel on stations unless you're creating a peer-to-peer WLAN without an AP. You can still use channel selection to improve performance on some clients, however, by using the Band Preference setting. Band Preference is configurable on most Broadcom mini-PCIe (internal notebook/tablet)WLAN adapters. Just go to the adapter's advanced properties (Properties à Configure à Advanced) and configure your Band Preference for 5 GHz/802.11a. The 5 GHz band has more channels and less outside interference, so if you take your station to a WLAN that supports all standards (802.11a/b/g/n), you'll most likely end up on a smoother channel. Tip #2: Set your SSID, and set it right. Here's onetopic that always seems to cause controversy when I'm teaching a class: the SSID. The problem, as I see it, is that there has been so much conflicting information over the years. First they said hide it; now they say broadcast it. First they said make it like a password; now they say keep it simple. What advice do you listen to? The most important rule when setting your SSID is to configure itdifferently from your neighbors. One aspect of the whole SSID concept is to allow two WLANs on the same channel to be separated from each other, so start with that. Beyond that most essential rule, here are a few questions to ask yourself: Do I want to allow roaming or do I want users to be able to choose their AP? For roaming to work, the SSID has to be the same on every AP. To allow users to choosetheir AP, a different SSID must be used on each AP. Do I have stations that leave the network? If stations leave the network, don't hide the SSID. When the SSID is hidden, stations must probe for the SSID. For most stations, that means probing whether they are around the network or away from it. You don't want to make stations less secure when they are away from the network, so don't force them toprobe by hiding the SSID. Do I care if people know my location? Wardriving aggregation website like Wigle.net can be a real nuisance when choosing an SSID. Traditionally the advice was always to configure a unique SSID. The problem is that if you make your SSID too unique, you'll make it really easy for someone to find the location of your home or business by searching for your SSID on a site...