These knottyrope tips might help you out. This is not an end all solution but I have come across these issues in the past years. Go slow and document what you do. Worst case is resetting your router to default and starting over.
Router running latest firmware? Update it as many are
shipped with and old version as they sometimes sit on a shelf for months. Also
a Wi-Fi router more than 5 years old might not work well with multiple
Using a Hidden SSID? You should never hide SSID - hiding
SSID is a violation of the 802.11 spec and this can be a pain with setup. Most
new devices can see them anyways.
Using the same SSID as your neighbor? This is not good, you
need a unique name or it can try to connect to both. I have seen NetGear 5 times
in one neighborhood and after a simple name change you can have fast Wi-Fi
Using 2.4 and 5 ghz on one single SSID? This can be a
burden, drop it to 2.4 and it could make a difference. Newer routers support a
separate SSID for both frequencies.
Using WiFi B? If not using B then disable it or a rouge
device might try to connect and knock your speed down to B speed.
WEP vs WPA? Not all N devices support WEP or WPA, Best to
use WPA2 if all devices support it. Don’t try both WPA and WPA2 as some devices
get confused. Some Wi-Fi routers do not support WPA2 AES-CCMP just AES, see if
yours supports it. Most newer routers do have accelerated AES encryption but not
for WEP. Older encryption methods will be slower.
WEP can be hacked in minutes not matter what password you
use. If you have no choice but to use WEP, use only one WEP key as some
devices will not know what to do with the other ones. Remember thath this
encryption method will be slower.
Channel speed settings 20, 40 or both? Try 20 as most will
work on it. Some devices will not like 40 only or even set to both. Check this
on both 2.4 ghz and 5ghz on dual SSID routers. Using the default channel your
router was setup with? Try a different channel other than the common 6 or 11
channel. Use the Auto Channel hopping feature if your router has it, mine didn’t
work but it may for you.
Using Multiple Wi-Fi routers? place them on separate Wi-Fi channels so they
Newer routers do QOS better so don’t be making this change
right away on a newer model. older models with QOS for WMM Wi-Fi multimedia and
VOIP priority on older models may not work well. if you don’t need or use it,
don’t enable it. I turn off all QOS settings with great results since we don’t
use the features.
Does your router only support 1 VPN connection? If this is
the case then you might not be able to access BIS over Wi-Fi when other devices
are using it or VPN. Many newer routers support 4 or more VPN connections.
DNS servers slow? Try OpenDNS.org and see if speed
MTU matched up? Not a common issue but this can be a fun one
as not all routers will set it to your ISP setting. 1500 is a standard but you
can try 1492 for DSL lines or ones that use PPOE.
Using Extended range? If you don’t have matching card for
your brand router it might not work well. Try turning it off.
UPNP turned off? Turn it on as your device may setup some
port forwarding rules.
Using ISP modem and your own router/Wi-Fi router? Don’t
enable NAT on your own routers as Double NAT can cause connection problems.
All port speeds matched? Check your Router WAN port speed,
mine was set to 10Mbit by the ISP before. Also make sure its set to correct
duplex mode and match it with other equipment.
Using cordless phones? Replace your 2.4GHz cordless phones
with either a 900Mhz or 5.8GHz style so they won’t interfere.
Use Wi-Fi sharing on a PlayBook? It’s important to switch
off AP Isolation if your router has it. Mine has it on by default
Custom firewall rules can be fun, try to allow default and slowly make
changes and take notes on what you enable or disable.