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Whether or not they like it, enterprise IT shops are increasingly forced to manage iPhone and iPad users and their plethora of iPhone Wi-Fi connectivity problems. In our wireless LAN troubleshooting tip,
1. Start by rechecking your physical connections. Always start here, following the instructions in our wireless network troubleshooting tip, step 1.
2. Next, verify that your iPad or iPhone Wi-Fi adapter is installed and working properly. Because iPhones, iPads and iPod touches have internal 802.11 chipsets, you do not need to verify installation, but you should still check that Wi-Fi is enabled. Tap Settings / Wi-Fi. If Wi-Fi is OFF, tap the slider to set Wi-Fi ON. When Wi-Fi is ON, a Wi-Fi signal strength indicator will appear at the top left corner of your device's home screen.
3. Verify that your wireless router's LAN settings are correct. Follow instructions in our wireless network troubleshooting tip, step 3, to access your router's admin utility to determine the IP address range and subnet being assigned to wireless clients.
4. Verify your client's TCP/IP settings to ensure iPhone Wi-Fi connectivity. Return to Settings / Wi-Fi on your iPhone, iPad or iPod and find your own network's name (SSID) on the "Choose a Network" list.
- If your network's name is not on the list, your router may be hiding its SSID. Click "Other" and enter your network's name manually.
- If your network is on the list without a check mark beside it, your iPhone OS client is not connected. Tap your network's name to try to connect. You may be prompted for a password; enter it and tap "Join." If you repeatedly try but fail, go to step 8.
- If a check mark already appears to the left of your network's name, continue.
When you're trying to connect to any network, a spinning wheel appears to the right of the target network's name on your iPad or iPhone Wi-Fi client. When the wheel disappears, tap the right-facing arrow after the network's name to view the client's assigned IP address.
- If a connected client's IP address is "Static" but not in your router's LAN IP range (see step 3), tap "DHCP" to set an IP automatically and tap "Renew Lease."
- If a connected client's IP address remains blank or the client repeatedly connects but then quickly disconnects, go to step 8.
- If a connected client's IP address is in your router's LAN IP range, continue.
5. Once your iPhone OS client has a valid IP address within your router's LAN IP range, use "ping" to verify network connectivity. This step is different on an iPhone, iPad or iPod because Apple does not include a user-accessible "ping" app. However, you can still verify network connectivity as follows.
- If you have not yet installed a ping app, start by using Safari to check Internet access. You can start by browsing, for example, at Bing. If you can successfully open or reload an Internet website page, congratulations: You are connected!
- If you get the error message "Cannot Open Page," you'll need to do more digging. Try browsing your router's Web admin utility (e.g., http://192.168.1.1). If you can open that page, you are connected to your router but the router has a problem. Refer to our wireless network troubleshooting tip for additional hints.
- If you cannot browse your router's Web admin utility or another device connected to your router's LAN, you will need to troubleshoot connectivity another way. Use iTunes to download and install a "ping" app, such as the free Network Ping Lite app by MochaSoft. Use that app to ping your router's LAN IP address as shown below. If pinging your router repeatedly fails, skip to step 6.
- If pinging your router succeeds, ping any other wired or wireless LAN client that you wish to communicate with. If that ping fails, AP isolation may be enabled or the destination may be using a firewall to block incoming messages. Follow the instructions given in our wireless network troubleshooting tip, step 5.
6. If your iPhone OS wireless client still cannot connect, get a valid IP address, or ping your router, it's time to look for wireless-specific problems. The router and client must use compatible 802.11 standards. In particular:
- Older iPhones and iPod touches have integrated 802.11bg. They can be connected to an 802.11b, 11g or 11n (single or dual band) router but not to an 11a router.
- Third-generation iPod touches have integrated single-band 802.11n but operate as 802.11bg clients. They are compatible with the same routers as older devices.
- The new iPad has integrated dual band 802.11n capability and can be connected to any 802.11 router (including 11a). However, early iPads have experienced iPad WLAN problems, specifically in reconnecting to certain 11n routers.
To determine which 802.11 standards your router supports, look for the following Wi-Fi certified logos on boxes or manuals, or search for Wi-Fi certified products at the Wi-Fi Alliance website. Once you have confirmed that your router and client should be compatible, examine your router's wireless settings as described in our wireless network troubleshooting tip, step 6 .
7. If a compatible wireless client and router can "hear" each other but still cannot connect or exchange traffic, look for a security mismatch. The client must support the security mode required by the router: Open, WEP, WPA, or WPA2. Unless the WLAN is open (unsecured), the router and client must be configured with (or dynamically receive) identical keys to encrypt traffic between them. Compare your router's WLAN security settings to your client's wireless connection properties and attempt to match them.
- To reconfigure the security parameters for a network you are connected to, tap the right-facing arrow after the network's name and then tap "Forget this Network."
- To reconfigure the security parameters for any other network, select the name of the desired network (or tap "Other" and enter the network name manually).
- If your router uses WEP, set the client's Security to WEP and copy the router's first WEP key into the client's "Password" field.
- If your router uses WPA-Personal, set the client's Security to WPA and copy the router's passphrase into the client's "Password" field; capitalization counts!
- If your router uses WPA2-Personal, set the client's Security to WPA2 and copy the router's passphrase into the client's "Password" field; capitalization counts!
- If your router uses WPA or WPA2-Enterprise, set the client's Security to WPA-Enterprise or WPA2-Enterprise and continue 802.1X setup in step 8.
If you choose the wrong security type or enter the wrong password, tapping "Join" usually generates an error message, not a new saved network. However, mismatches can occur when a router to which you've previously connected is reconfigured. In that case, it is often best to "Forget this Network" and start fresh.
8. Ensure RADIUS is working. WPA and WPA2-Enterprise log the client into the network and deliver encryption keys using an 802.1X-capable RADIUS server. Refer to our network troubleshooting tip, step 8, to check your router's RADIUS settings.
9. If RADIUS is working but the client's access requests are rejected, look for an 802.1X Extensible Authentication Protocol (EAP) problem. Your client must support one of the EAP types required by your RADIUS server and must supply a valid login.
- If your RADIUS server requires PEAP, just set the client's Security to WPA-Enterprise or WPA2-Enterprise and enter your assigned username and password.
- If your RADIUS server requires any other EAP type, you must complete WPA2-Enterprise/802.1X setup using a configuration utility or configuration profiles. To learn more, consult this Apple iPhone in Business guide.
10. If your iPhone OS client still cannot seem to connect, seems very slow all the time, or disconnects frequently, you may be experiencing lower-level wireless problems. Refer to our network troubleshooting tip, steps 10 and 11, for further instructions. To facilitate debugging, you may also want to install a few more free apps. For example:
- Ookla SpeedTest – Handy for measuring slow connections
- Bitrino WifiTrak – View current channel, signal/noise, and security settings
- 10base-t IP Scanner Lite – Try to reach other clients on your own network
About the author:
Lisa A. Phifer is vice president of Core Competence Inc. She has been involved in the design, implementation and evaluation of data communications, internetworking, security and network management products for more than 20 years and has advised companies large and small regarding security needs, product assessment and the use of emerging technologies and best practices.
This was first published in June 2010