Troubleshooting Wireless Networking Issues

요약: This article provides helpful information and links for basic wireless network troubleshooting. More specifically, this article focuses on 802.11a, b, g, n, or ac networks This article does not cover Mobile Broadband (cellular-based wireless) or Bluetooth (also known as WPAN). ...

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Background Information

The primary pieces of information needed for Wireless network troubleshooting are listed below.

SSID
Security Type
Security Key or Passphrase
Distance from the Access Point or Router
Line of Site
Channel Signal Overlap

SSID: The Service Set Identifier This is the name of the network that you are interested in joining. Wireless networks can be configured to broadcast this SSID or to hide the SSID. If the SSID is broadcast, it is listed in the "Wireless networks available." If the SSID is NOT broadcast, you must know exactly how it is spelled and capitalized in order to join the network.

Security Type: This is the type of encryption used on the network to keep data secure. Windows may figure this out for you. This also controls what type of security key and passphrase that you can use. The common options for security are listed below in order of their security level. No security is the least secure, and WPA2 is the most secure.

No security (also known as open)
Wired Equivalent Privacy (WEP) 64-bit
Wired Equivalent Privacy (WEP) 128-bit
Wi-Fi Protected Access (WPA) options include AES and TKIP
Wi-Fi Protected Access version 2 (WPA2) also includes AES and TKIP

Security Key or Passphrase: This is the key used to encrypt the data. Without this key or phrase being correct, it is not possible to understand the data flowing across the network. This is like the secret knock or "open sesame" secret phrase.

Distance from the Access Point or router: The range of acceptable signal strength varies between Wi-Fi types, but a general guideline is 120 ft indoors and 300 ft outdoors.

Line of Site: Anything between the access point and the device reduces signal strength and range. Some materials have more impact than others. Dense wood (such as oak) and metal have the most impact. Sheetrock and cloth have a minimal impact. Utility closets, wood cabinets, metal piping, and restrooms between the access point and the device reduce signal strength.

Channel Signal Overlap: A Wi-Fi signal occupies five channels in the 2.4 GHz band; any two channels whose channel numbers differ by five or more, such as 2 and 7, do not overlap. The oft-repeated adage that channels 1, 6, and 11 are the only nonoverlapping channels is not accurate; channels 1, 6, and 11 are the only group of three nonoverlapping channels in the U.S. Other Wi-Fi networks in the area on overlapping networks may be interfering.

Wireless Standards

IEEE 802.11 a/b/g/n/ac are the accepted industry standards. The features and strengths compared with weaknesses' of these standards are shown here.

Standard	Name	Release Date	Frequency Range	Max Speed	Realistic Speed	Indoor Range	Outdoor Range
802.11a	Wi-Fi 1	1999	5 GHz	54 Mbps	23-28 Mbps	20 m	120 m
802.11b	Wi-Fi 2	1999	2.4 GHz	11 Mbps	5.9 Mbps	35 m	120 m
802.11 g	Wi-Fi 3	2003	2.4 GHz	54 Mbps	22 Mbps	38 m	140 m
802.11n	Wi-Fi 4	2009	2.4 GHz & 5 GHz	300 Mbps	130-150 Mbps	70 m	250 m
802.11ac	Wi-Fi 5	2013	2.4 GHz & 5 GHz	1300 Mbps		35 m
802.11ax	Wi-Fi 6	2019	2.4 GHz & 5 GHz	10..53 Gbps

The effective range varies dramatically based on the Line of Sight and the materials through which the material must pass.

802.11a Signal Range

(Figure 1 - 802.11a Signal Range)

802.11a Signal Range Example Notice how even a few walls absorb the signal.

802.11g Signal Range

(Figure 2 - 802.11 g Signal Range)

802.11 g Signal Range Example Notice how the walls have dramatically less effect on the range.

Troubleshooting

Find below some troubleshooting steps for the following scenarios:

Scenario	Troubleshooting Steps
SSID is visible but cannot connect to it.	Verify Encryption Type (WEP, WPA, or WPA2) and Security Key or Passphrase Verify that the SSID is standard and capitalized correctly using only letters and numbers Reboot the Access Point (AP) or Router Reboot the client (computer, printer, and so on) Verify that the Access Point or Router is within the realistic indoor range for the wireless standard it uses and that the client supports that wireless standard (for example both devices support 802.11n) Verify that the client can support the security type used by the Access Point or Router
No SSIDs are visible.	Verify that Wi-Fi is enabled (BIOS for computers, menu settings for printers and projectors) If the system has a Wi-Fi switch, verify that it is in the On position Verify that the Wi-Fi radio is enabled in the driver or management software Verify that the Access Point or Router is within the realistic indoor range for the wireless standard it uses and that the client supports that wireless standard. For example, verify that both devices support the 802.11n standard. Reboot both the client device and the Access Point or Router.
Some SSIDs are visible, but the specific ones you require.	Verify that the Access Point or Router is set to "Broadcast SSID" Verify that the Access Point or Router is within the realistic indoor range for the wireless standard it uses and that the client supports that wireless standard. For example, verify that both devices support the 802.11n standard. Reboot both the client device and the Access Point or Router. Verify that the client can support the security type used by the Access Point or Router
Can connect to the correct SSID but cannot obtain an IP Address.	Certain information is required before troubleshooting this issue can begin. 1. IP Address 2. Subnet Mask Address 3. Default Gateway Address 4. DNS Server information Do any of the devices have an APIPA address? (169.254.xxx.xxx) Reboot or restart the router or gateway Check all cable connections and reseat making sure they are firmly in place. Use ipconfig to release and renew the address Navigate to the Command prompt: Select Start and enter CMD into the Run search box Enter the following at the Command Prompt: > ipconfig/release > ipconfig/renew Do all the devices have the same Subnet Mask address? Do all the IP addresses start with the same numbers (they are in the same range or subnet). For instance, they all start with 192.168.1.x or 10.1.52.x Make sure there are no devices with the same IP address. If there are, this causes an IP conflict, and 1 or both devices fail to connect. Use PING to verify that an IP address is seen on the Network Select Start and enter CMD into the Run search box Enter the following at the Command Prompt: > Ping 192.xxx.xxx.xxx If the IP address is seen and found, you see four lines of replies showing the time taken to check the network connection (in milliseconds) If you receive a "Request Timeout" message, either the IP address is not recognized or it cannot be found on the network.

Can connect to the network but cannot retrieve data.

Verify SSID, Security type, and Encryption Key or Passphrase
Delete the Network Profile and reconnect
Verify that the Access Point or Router is within the realistic indoor range for the wireless standard it uses and that the client supports that wireless standard. For example, verify that both devices support the 802.11n standard.
If possible, update the Access Point or Router to the current firmware version
Update client device firmware or drivers
Reboot both the client device and the Access Point or Router
Check if the client device can connect and transfer traffic to other networks.
If possible, Disable firewalls for troubleshooting purposes only.

Device Disconnecting from the Network Intermittently

Update firmware and drivers on both the client device and the Access Point or Router
Move the client and Access Point or Router closer together
If possible, change the channel setting on the router. Channels 1, 6, and 11 are usually the best options.
Verify that there is not a secondary program trying to manage the wireless adapter.
Adjust the antennas on the Access Point or Router to be perpendicular to the direction of the client (not pointing toward or away from the client)
Check if this problem happens on other wireless networks.
Log in to the router and check the "Uptime." If the uptime is always short, the router may be rebooting and dropping all clients.
Reseat the wireless adapter on the client device.

Make sure the disconnects do not coincide with the use of other devices in the same frequency band. Examples include:

Microwave Ovens
Bluetooth devices
Baby monitors
Cordless telephones

Slow Connection Speed

Try moving the client's device to another location. The goal is to change the Line of Sight obstacles between the router and the client.
Try moving the router to another location. The goal is to change the Line of Sight obstacles between the router and the client.
If possible, change the channel setting on the router. Channels 1, 6, and 11 are usually the best options.
Update firmware and drivers on both the client device and the Access Point or Router
Adjust the antennas on the Access Point or Router to be perpendicular to the direction of the client (not pointing toward or away from the client)

Eliminate other devices in the vicinity that use the same frequency band. Examples include:

Microwave Ovens
Bluetooth devices
Baby monitors
Cordless telephones

Note: When the following steps do not resolve the issue, the Operating System on your computer has some sort of corruption. To explore the options on how to resolve any corruption, and when to use them, go to our Networking and Wireless Support Center and select your Operating System.

Dell laptops may experience wireless performance issues and some package loss when using the system with the LCD in the closed position. For most laptops, the Wi-Fi antennas are located in the upper portion of the lid towards the corners, and they are designed to operate in the vertical orientation (LCD lid open). Closing the LCD might cause signal degradation and possible network package loss.

If you experience wireless connection issues with the LCD closed on your Dell laptop, it is recommended you use a wired connection (either through a direct connection or through an attached docking station) if the laptop needs a network connection with the LCD closed.