wifi-configuration interview questions
Top wifi-configuration frequently asked interview questions
When I connect to a hotel network that does not require a WPA key, on my PC, the first browser access will be trapped and directed to the login page. This is understandable, and I can guess the network equipment provisions access by MAC address.
On my Android (5.0) phone, a Sign-in to Network screen opens and it shows that same web page as what I see on the PC. What is the protocol that makes this happen?
Source: (StackOverflow)
One of my neighbors has an unsecure wifi network called WLAN. At one point in the past, I accidentally connected to it, and disconnected immediately when I noticed. Now, when I open my laptop at home, it sometimes connects to the WLAN network first, before trying my (secured) home wifi network.
The information I've found regarding this issue seems to suggest this network should have a profile on the "Manage wireless networks" screen - but it does not.
How do I tell Windows 7 to never connect to networks with SSIDs called WLAN? Or to never connect to unsecured networks without confirming with me first?
Source: (StackOverflow)
Is there a simple and permanent way to disable the Microsoft Virtual WiFi Miniport Adapter permanently.
I believe this device may be the source of some wifi problems my users have been having.
Source: (StackOverflow)
I've set up a router in my room (It's a TP-LINK W8980). I'm inside a college room, so I connected the WAN to the ethernet ports of my room, and the router is creating a wifi network. It's using PPPoE without DHCP.
When setting it up I connected it to my laptop using an ethernet cable, I opened http://192.168.1.1/ on a browser and I've reached the configuration page and I was able to login with the default user and password and set up the wifi networks I was looking for (and they are working fine).
I'd like to change some settings (especially the password...). However, right now, I cannot reach http://192.168.1.1/. It never lands on the login page (ping 192.168.1.1 gives an unknown host error). I've already tried:
- disconnecting from the wifi network and only connect directly to the router via ethernet on a LAN port.
- disconnecting the router from the WAN.
- connecting the laptop to the WAN port of the router (in this case I get an error message about missing IP configuration, which is probably due to not having DHCP enabled in the router?).
So, my question: how the heck am I supposed to change the settings of the router now?
It seems way too strange that the only way to setup a router after the initial configuration is to factory reset it and restart from zero...
Note: I've used all default settings for the networks and the router except that I had to select PPPoE and Dynamic IP and disable DHCP to make internet work on the wifi networks.
Note: In order to access Internet I have to go through a captive login portal.
Note: This is my first time ever setting up a router, or doing any kind of network configuration. So things like "Set a fixed IP for your laptop..." or basically any kind of language regarding network configuration to me sounds like "take your magic wand and touch laptop/router".
So: explain! If I have to change a setting in some system file tell me which file, and how to modify it. If I have to change some setting using some command line tool tell me which command line tool. If I have to change some system setting, try to give me some hints on how I can recognize it.
Some more information about my laptop configuration.
When I have the laptop connected via ethernet to a LAN port of the router (no wifi):
$ip route
default via 158.110.96.1 dev eth0 proto static
158.110.96.0/24 dev eth0 proto kernel scope link src 158.110.96.145 metric 1
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.42.1
$ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 1c:75:08:48:59:95 brd ff:ff:ff:ff:ff:ff
inet 158.110.96.145/24 brd 158.110.96.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::1e75:8ff:fe48:5995/64 scope link
valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 5c:ac:4c:3c:5d:b2 brd ff:ff:ff:ff:ff:ff
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 56:84:7a:fe:97:99 brd ff:ff:ff:ff:ff:ff
inet 172.17.42.1/16 scope global docker0
valid_lft forever preferred_lft forever
Trying to access 192.168.1.1 triggers the captive portal login, but I cannot access the config page.
Here's the output when the ethernet cable is connected to the WAN of my router and my laptop is connected to the wifi network of the router (ideally I'd like to be able to access router settings from this configuration, without having to add cables to my router etc.):
$ip route
default via 158.110.96.1 dev wlan0 proto static
158.110.96.0/24 dev wlan0 proto kernel scope link src 158.110.96.119 metric 9
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.42.1
$ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 1c:75:08:48:59:95 brd ff:ff:ff:ff:ff:ff
inet6 fe80::1e75:8ff:fe48:5995/64 scope link
valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 5c:ac:4c:3c:5d:b2 brd ff:ff:ff:ff:ff:ff
inet 158.110.96.119/24 brd 158.110.96.255 scope global wlan0
valid_lft forever preferred_lft forever
inet6 fe80::5eac:4cff:fe3c:5db2/64 scope link
valid_lft forever preferred_lft forever
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 56:84:7a:fe:97:99 brd ff:ff:ff:ff:ff:ff
inet 172.17.42.1/16 scope global docker0
valid_lft forever preferred_lft forever
Trying to access 192.168.1.1 triggers the captive portal login, but I cannot access the config page.
With my current configuration trying to connect the laptop via ethernet to the WAN of the router fails saying that IP configuration is missing.
Note that I only care about being able to access the internet and to access the router configuration page. I don't care about other things in the network configuration.
Source: (StackOverflow)
I upgraded to Windows 10 and ever since then my computer can't find my own home wifi network. A bunch of available wifi networks will show up, but not mine. I don't have it hidden and it shows up on my Blackberry & my Samsung Galaxy. Ethernet works fine, but not wifi.
I've tried the following:
- Use device manager and scroll to network adapters and expand it and select your wifi card. from there hit uninstall but do not remove the driver. after that look up top for a computer with a magnifying glass and it will scan for changes which will then reinstall your driver for your wireless.
- I tried to "manually connect to a wireless network" which still didn't work (I could name it, and enter the password) but nothing would happen.
- I've upgraded the drivers of my Dell Centrino card and I still don't see my wifi network.
Any suggestions on what to do?
Source: (StackOverflow)
A Windows 8 tablet keeps scanning for Wi-Fi networks even though it's already connected to a preferred one.
I can see some other networks appearing and disappearing in the connectivity area on the right side of the screen. I'd like to turn that feature off so the device sticks to the networks already saved as preferred and doesn't search for new ones; having to enter the SSID manually whenever needed is fine with me.
I know I can turn the Airplane mode on but then I won't be able to use my home network.
Tried to search for wifi scan off but all it shows me is about Android. Tried changing the query to be wifi scan off windows but there's literally nothing relevant, not even questions.
How do I turn Wi-Fi discovery off? I don't need the device constantly scanning the new networks. Thanks
Source: (StackOverflow)
I'm trying to figure out how to set up my RTL8188CUS Wifi dongle to run in both AP and Client mode at the same time.
How can I do this in Linux?
I have hostapd running fine and I remember reading about AP+Client mode somewhere a while ago for the RTL8188, but I can't remember where.
Additional info
I'm on Debian 4.7.2-5 for ARM.
Linux kernel 3.4.90+.
I found the following threads that might be of use and (I think) relevant:
Link 1: How do I use a single wireless adapter for both an access point and client on raspberry pi?
Link 2: Creating WiFi Access point on a single interface in Linux
I tried the first first link, no success.
UPDATE
I have managed to get iw list to work on Debain 8 Jessie x64.
It outputs the following:
software interface modes (can always be added):
* AP/VLAN
* monitor
interface combinations are not supported
However according to Realteks release notes of their latest drivers
they state that the RTL8188CUS supports concurrent modes such as STA+AP as of version 4.0.0_5967.20121201
Doesn't this contradict what iw list states?
If not, how would an STA+AP mode be achieved?
UPDATE
I figured it out. Please see my answer for more info.
Source: (StackOverflow)
I just upgraded my Comcast internet, and my wired speeds vary from 58 Mbps to 70 Mbps (per speedtest.net).
I have a WRT610N router, and I'm only getting around 20-25 mbps from the wifi.
Things I have tried:
1) On channel 11, no other wifi signals in range are any higher than 6.
2) Switched between 20Mhz signal and 40Mhz signal. (Slight improvement with 40, but only about 2 mpbs)
3) Turned off CTS (Minor improvment)
4) Turned on Frame Bursting (Maybe a minor improvement, did at same time as CTS, so I'm not really sure which one caused the slight improvement).
5) Updated firmware of everything involved (router, wifi card, etc.)
From what I understand even a bad wireless-N network should be able to reach at least 75mpbs in practical speed, so what am I doing wrong here? Is it just my router? I am using DD-WRT, should I switch back to the standard Linksys firmware?
Any other suggestions? I've done 2 days worth of googling to try and find a solution to my problem, and still haven't figured it out.
UPDATE:
1) Switched back to Linksys firmware (speeds went up to 30 Mbps)
2) When I try to use the 5GHz, my wifi doesn't even show up. (Trying to fix that now).
Thanks for the responses.
Source: (StackOverflow)
I installed ubuntu 14.04 in my new laptop Lenovo Thinkpad E540
I connect to a wifi network but after a while I lost connection, I try to reconnect but it cann't connect again to any wifi netwotk. for connecting again i have to reboot computer.
here is part of my dmesg code:
[ 618.444235] wlan0: authenticate with f8:1a:67:b5:da:63
[ 618.464150] wlan0: send auth to f8:1a:67:b5:da:63 (try 1/3)
[ 618.465700] wlan0: authenticated
[ 618.467617] wlan0: associate with f8:1a:67:b5:da:63 (try 1/3)
[ 618.471473] wlan0: RX AssocResp from f8:1a:67:b5:da:63 (capab=0x411 status=0 aid=2)
[ 618.471683] wlan0: associated
[ 618.471735] cfg80211: Calling CRDA for country: US
[ 618.473575] cfg80211: Regulatory domain changed to country: US
[ 618.473578] cfg80211: DFS Master region: unset
[ 618.473579] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 618.473581] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2700 mBm), (N/A)
[ 618.473583] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 1700 mBm), (N/A)
[ 618.473584] cfg80211: (5250000 KHz - 5330000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 618.473585] cfg80211: (5490000 KHz - 5600000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 618.473587] cfg80211: (5650000 KHz - 5710000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 618.473588] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 3000 mBm), (N/A)
[ 618.473589] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
[ 643.634049] wlan0: Connection to AP f8:1a:67:b5:da:63 lost
[ 643.666952] cfg80211: Calling CRDA to update world regulatory domain
[ 643.669050] cfg80211: World regulatory domain updated:
[ 643.669053] cfg80211: DFS Master region: unset
[ 643.669054] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 643.669056] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 643.669058] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 643.669060] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 643.669061] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 643.669062] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 645.069564] wlan0: authenticate with f8:1a:67:b5:da:63
[ 645.089661] wlan0: send auth to f8:1a:67:b5:da:63 (try 1/3)
[ 645.091299] wlan0: authenticated
[ 645.093193] wlan0: associate with f8:1a:67:b5:da:63 (try 1/3)
[ 645.098035] wlan0: RX AssocResp from f8:1a:67:b5:da:63 (capab=0x411 status=0 aid=2)
[ 645.098228] wlan0: associated
[ 645.098291] cfg80211: Calling CRDA for country: US
[ 645.100131] cfg80211: Regulatory domain changed to country: US
[ 645.100133] cfg80211: DFS Master region: unset
[ 645.100134] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 645.100137] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2700 mBm), (N/A)
[ 645.100138] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 1700 mBm), (N/A)
[ 645.100140] cfg80211: (5250000 KHz - 5330000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 645.100141] cfg80211: (5490000 KHz - 5600000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 645.100142] cfg80211: (5650000 KHz - 5710000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 645.100144] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 3000 mBm), (N/A)
[ 645.100145] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
[ 726.303619] wlan0: Connection to AP f8:1a:67:b5:da:63 lost
[ 726.352482] cfg80211: Calling CRDA to update world regulatory domain
[ 726.354514] cfg80211: World regulatory domain updated:
[ 726.354517] cfg80211: DFS Master region: unset
[ 726.354518] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 726.354520] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 726.354522] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 726.354523] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 726.354524] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 726.354526] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[ 727.755050] wlan0: authenticate with f8:1a:67:b5:da:63
[ 727.775175] wlan0: send auth to f8:1a:67:b5:da:63 (try 1/3)
[ 727.776824] wlan0: authenticated
[ 727.778713] wlan0: associate with f8:1a:67:b5:da:63 (try 1/3)
[ 727.782440] wlan0: RX AssocResp from f8:1a:67:b5:da:63 (capab=0x411 status=0 aid=2)
[ 727.782642] wlan0: associated
[ 727.782693] cfg80211: Calling CRDA for country: US
[ 727.784431] cfg80211: Regulatory domain changed to country: US
[ 727.784433] cfg80211: DFS Master region: unset
[ 727.784434] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 727.784435] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2700 mBm), (N/A)
[ 727.784437] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 1700 mBm), (N/A)
[ 727.784438] cfg80211: (5250000 KHz - 5330000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 727.784439] cfg80211: (5490000 KHz - 5600000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 727.784439] cfg80211: (5650000 KHz - 5710000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (0 s)
[ 727.784440] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 3000 mBm), (N/A)
[ 727.784441] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
[12208.927155] wlan0: deauthenticating from f8:1a:67:b5:da:63 by local choice (Reason: 3=DEAUTH_LEAVING)
[12218.549245] cfg80211: Calling CRDA to update world regulatory domain
[12218.551729] cfg80211: World regulatory domain updated:
[12218.551734] cfg80211: DFS Master region: unset
[12218.551735] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[12218.551738] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[12218.551741] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[12218.551743] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm), (N/A)
[12218.551745] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
[12218.551746] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm), (N/A)
and also here is my iwconfig output:
eth0 no wireless extensions.
wlan0 IEEE 802.11bgn ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=20 dBm
Retry short limit:7 RTS thr=2347 B Fragment thr:off
Power Management:off
lo no wireless extensions.
how can i fix it? i can just coonet to netwotk by wired connection now :(
can you please help me to fix it?
Source: (StackOverflow)
Suppose I have my latop-1 that have access to the internet through wifi-A.
I want laptop-2 to connect to the internet, however it can't direct connect to wifi-A because the computer is using a terminal environment, it can't access to the browser based login system of wifi-A.
Can I creat a wifi hostspot wifi-B using the laptop-1, to share the internet with my laptop-2? Note that the laptop-1 has internet access because it already connected to wifi-A, not wired.
In short, can I create a wifi hot spot using a laptop which already connected to the another wifi?
Source: (StackOverflow)
When both are connected does it always use Ethernet or does it monitor both and use the most reliable or fastest one?
Source: (StackOverflow)
I run a WiFi hotspot from my Windows 8.1 PC (Windows 10 Technical preview from last few days). When I try to connect from my android, the signal strength goes low and then results in authentication problem.
But after or before that, i.e. when the WiFi access point is only listed, it shows excellent signal strength.
Why does it happen so, or is there a remedy for that ?
OS: Windows Technical Preview x64
Drivers:
Broadcom 802.11n Network Adapter (HWID : PCI\VEN_14E4&DEV_4727&SUBSYS_1795103C&REV_01)
Realtek PCIe FE Family Controller (HWID: PCI\VEN_10EC&DEV_8136&SUBSYS_1670103C&REV_05)
Don't know what/how to list Please Check this result from Driver Identifier
Hotspot created by Virtual Router manager
Client device: Micromax Canvas A1
Note: I previously used a Nokia 500 device which used to connect to my WiFi hotspot successfully. And as for my android, it can connect to other hotspots.
Source: (StackOverflow)
I start my computer normally and the Wi-Fi adapter works just fine. However, once I sleep or hibernate, and resume, I am no longer connected to any network. I scan for a network and the list displays just fine and everything seems to be in order, but when I try to connect to any of them, even the last one it was connected to, I get a "can't connect to this network" error.
This happens with any other network and has no discernible pattern (i.e. it sometime works just fine, but mostly it fails as previously described)
In order to connect again, I disable the adapter and re-enable it. This way, it starts working normally again.
Why does this happen? Is there a way to avoid it? It has become a cumbersome routine to disable a enable the device each time I have to sleep my laptop.
System info:
Dell Inspiron 5548
Intel(R) Dual Band Wireless-AC 7260
Windows 8.1
Source: (StackOverflow)
I have a old Linksys router the I converted into a repeater using dd-wrt firmware. Its been running great but I'm just curious is it possible that it could be interfering with the main router?
Source: (StackOverflow)
Using the command line on Debian, how can make the system forget the wireless networks I previously connected to?
Thanks.
Source: (StackOverflow)