Wi-Fi net­work trou­bleshoot­ing guide

GLENN FLEISHMAN’s tips will help solve your Wi-Fi prob­lems

Tech Advisor - - Contents -

Wi-Fi is ev­ery­where and built into ev­ery­thing. It’s like oxy­gen for In­ter­net ac­cess, me­dia stream­ing, gam­ing, and all types of net­work­ing. And it should just work all the time – right? If you’ve had an av­er­age ex­pe­ri­ence with Wi-Fi on mo­biles de­vices, lap­tops, game sys­tems, and more, you know that while a solid Wi-Fi con­nec­tion might be the norm, those times when it’s not can leave you tear­ing your hair out.

Here, I look at a num­ber of com­mon sce­nar­ios that cause Wi-Fi prob­lems and how to solve them, whether you’re run­ning your own net­work or try­ing to con­nect to some­one else’s us­ing any plat­form.

Wi-Fi ba­sics

Be­fore we get started, a very quick primer on a few Wi-Fi terms I’ll bring up re­peat­edly.

802.11: the name of the IEEE engi­neer­ing trade group’s work­ing group for wire­less lo­cal area net­works (WLANs). WLANs be­gan in earnest with 802.11b in 1999 (802.11a came out at the same time, but had less trac­tion), and the group is all the way up to 802.11ac and 802.11ad today. We ex­pect to see 802.11ax gear an­nounced at CES. These spec­i­fi­ca­tions de­fine how data is en­coded into ra­dio trans­mis­sions and ex­changed among de­vices.

Wi-Fi: a trade­marked name used to cover net­work adap­tors that have passed a cer­ti­fi­ca­tion test to work with each other us­ing var­i­ous 802.11 spec­i­fi­ca­tions.

Fre­quency bands: Wi-Fi net­works use two un­li­censed fre­quency bands: 2.4- and 5GHz. Many Wi-Fi routers and most mod­ern mo­bile and desk­top de­vices can create net­works or con­nect over ei­ther band – these are ‘dual-band’ base sta­tions or adap­tors. 802.11b and g ex­clu­sively use the 2.4GHz band. 802.11a and ac ex­clu­sively use 5GHz. 802.11n works over ei­ther band.

Chan­nels: Fre­quency bands are di­vided into num­bered chan­nels. In the UK, 2.4GHz has 13 avail­able over­lap­ping chan­nels num­bered 1 to 13, while 5GHz has about two dozen scat­tered across a broader range from 36 to 165. They run in groups for his­toric rea­sons in how the band­width was granted for un­li­censed use to ev­ery­one.

Can’t see a net­work you know is avail­able

You know a net­work should be reach­able from where you’re at, but it doesn’t show up in your list of avail­able net­works to which you can con­nect. Try these pos­si­bil­i­ties:

Check if you dis­abled Wi-Fi with­out re­al­iz­ing it. Some Win­dows lap­tops and other de­vices have hard­ware WiFi switches or but­tons that you can press by ac­ci­dent. In Win­dows 10, the net­work icon will show a red X through the Wi-Fi in the taskbar. In macOS, the Wi-Fi ‘fan’ in the sys­tem menu bar will be an empty out­line.

Cy­cle your Wi-Fi adap­tor. On many de­vices, you can choose a soft­ware set­ting to dis­able the Wi-Fi ra­dio tem­po­rar­ily. Air­plane Mode is the sim­plest way in op­er­at­ing sys­tems that of­fer it, though us­ing it dis­rupts cel­lu­lar and Blue­tooth con­nec­tions on your de­vice.

Out of range. Wi-Fi doesn’t have a hard cut-off as to when it will and won’t work. Some­times you can get per­fect re­cep­tion in one place at one time but not an­other. That’s be­cause the ra­dio sig­nals bounce off sur­faces, pass through walls, and can be ab­sorbed by peo­ple and ma­te­ri­als. Move around and see if the net­work shows up.

Check your band. While many user de­vices can con­nect us­ing ei­ther fre­quency band, you can still find mod­ern hard­ware that can only con­nect via 2.4GHz. If you are in a lo­ca­tion where the only avail­able sig­nal that reaches is a 5GHz net­work, all your dual-band hard­ware will con­nect just fine, but sin­gle-band 2.4GHz gear won’t. Be­cause of the dif­fer­ent char­ac­ter­is­tics of the band, it’s pos­si­ble to be in a room in a house, of­fice, or pub­lic space where a 2.4GHz sig­nal doesn’t reach, but the same base sta­tion’s 5GHz sig­nal is crisp and clear. The Ap­ple Watch in all its ver­sions sup­ports only 2.4GHz Wi-Fi. Older and in­ex­pen­sive smart­phones and ta­bles may lack 5GHz ra­dios, too, and many smart home prod­ucts have only 2.4GHz sup­port.

It’s a closed net­work. While it’s never been a truly valid way of im­prov­ing se­cu­rity, some net­works are set up so that they don’t broad­cast their name. In that case, if you don’t have a con­nec­tion pro­file stored, you must use the method in the op­er­at­ing sys­tem to join a net­work man­u­ally, of­ten listed as ‘Other’ in a menu. You’ll need to en­ter the name pre­cisely and, if it’s us­ing en­cryp­tion, choose its se­cu­rity method and en­ter the pass­word.

The net­work is down. Check from mul­ti­ple de­vices or ask other peo­ple us­ing the net­work. A router may need to be re­booted – or re­placed.

Con­nected, but no In­ter­net ac­cess

Wi-Fi is just a ra­dio tech­nol­ogy, which means you can have a per­fectly strong sig­nal and a valid con­nec­tion, but still lack net­work ac­cess.

First, check your net­work ad­dress and see if it’s in the ‘self-as­signed’ range. If there’s some­thing wrong with the way the lo­cal net­work as­signs out ad­dresses to de­vices as they at­tach, your com­puter or mo­bile de­vice will create a self-as­signed ad­dress, which can’t route data else­where. In some cases, small net­works can run out of ad­dresses to as­sign. Some op­er­at­ing sys­tems pro­vide a clue there’s a prob­lem, like the Wi-Fi sig­nal adap­tor show­ing an ex­cla­ma­tion point in it. In oth­ers, you’ll need to drill into net­work sta­tus or set­tings.

In An­droid: Set­tings > About Phone > Sta­tus.

In iOS: Set­tings > Wi-Fi and tap the ‘i’ info but­ton.

In Win­dows: Set­tings > Net­work & In­ter­net and then choose the Wi-Fi adap­tor.

In macOS: Open the Net­work sys­tem pref­er­ence pane, se­lect the Wi-Fi adap­tor, click Ad­vanced, and click the TCP/IP tab.

If the IP ad­dress on your de­vice for IPv4 net­work­ing (a set of four num­bers sep­a­rated by pe­ri­ods) starts with 169.254, then it’s a self-as­signed ad­dress, which in­di­cates your OS couldn’t re­ceive an as­sign­ment from the lo­cal net­work’s DHCP (Dy­namic Host Con­fig­u­ra­tion Pro­to­col) server. (Some work and aca­demic net­works might re­quire en­ter­ing a static set of values, but you should know if you’re on one of those.)

Be­fore as­sum­ing the net­work is at fault, how­ever, check your fire­wall set­tings, if you have one in­stalled or are us­ing tools built into the OS. Some fire­walls pre­vent con­nect­ing to new net­works and rout­ing traf­fic over them with­out an ex­plicit en­try. In most cases, you should re­ceive a prompt that warns you about a new net­work and asks you ap­prove it. But de­pend­ing on your con­fig­u­ra­tion, it’s pos­si­ble the net­work rout­ing has been blocked silently.

Once you elim­i­nate the fire­wall or other fil­ters, you can be sure it’s the net­work that’s the trou­ble. If you’re not the per­son who kicks routers when they mis­be­have, you’ll need to find some­one who is.

The IP ad­dress is valid, but noth­ing loads

If you’re us­ing a pub­lic hotspot at a café, air­port, con­fer­ence cen­tre, or else­where, you might have run

afoul of a por­tal or lo­gin page with­out re­al­iz­ing it. Most op­er­at­ing sys­tems’ last sev­eral ver­sions un­der­stand that you might en­counter a por­tal and act ac­cord­ingly. Un­til you an­swer the right ques­tions or click the right but­tons, In­ter­net ac­cess is locked away.

With a por­tal page, the hotspot ef­fec­tively hi­jacks do­main name ser­vice (DNS) lookups, so that ev­ery­where you’re try­ing to go redi­rects to the por­tal. Ap­ple’s macOS and iOS rec­og­nize this be­hav­iour, and pop up a modal di­a­log that dis­plays the por­tal web page. Once ac­cess suc­cess­fully starts, the op­er­at­ing sys­tem can tell that DNS is work­ing prop­erly and dis­misses it­self or shows a Done but­ton that can be tapped or clicked. Some­times por­tals are wonky or, due to fire­wall or other fil­ter­ing soft­ware, your sys­tem doesn’t trust these redi­rec­tions. This would pre­vent the por­tal page from ap­pear­ing. Open a browser and try to load any page, like

techad­vi­sor.co.uk, and see what hap­pens. If you see load­ing and re­di­rect­ion start – look at the Lo­ca­tion field in your browser and see if the do­main or IP ad­dresses change – it’s likely some­thing on your sys­tem that’s block­ing com­ple­tion. If noth­ing ever loads in the browser, con­sult with the venue. You may need to ob­tain a pass­word, pay, or use a spe­cial con­fig­u­ra­tion.

Your net­work con­nec­tions are in­con­sis­tent

There are four main cul­prits in in­con­sis­tent Wi-Fi per­for­mance and net­work ac­cess: an er­ratic broad­band con­nec­tion, dis­tance from a base sta­tion, the wrong base sta­tion in a set se­lected, and a con­gested lo­cal net­work­ing en­vi­ron­ment.

Broad­band. The first is hard to test un­less you can plug an eth­er­net ca­ble into the router and use a band­width tester, like one from Ookla, or a net­work monitor that shows you per­for­mance over time. If you can, how­ever, elim­i­nate that as a pos­si­bil­ity be­fore you move for­ward.

Dis­tance. This seems like an easy one, too: move closer. But if you don’t know where the Wi-Fi base sta­tions are lo­cated or you’re in rooms away from those in which they’re placed, ‘closer’ may be hard to fig­ure out. Be­cause of sig­nal re­flec­tion and ab­sorp­tion, it’s not al­ways ob­vi­ous where to move your own base sta­tions

for bet­ter cov­er­age. NetSpot ($49, around £46, from fave.co/2B5RDdC for the Pro ver­sion for Win­dows and macOS; there’s also a fea­ture-lim­ited free ver­sion) can help you vi­su­al­ize your cov­er­age area by build­ing a heat map as you walk around. There’s also a free ver­sion of Eke­hau’s Heatmap­per (fave.co/2BN1996) that pro­vides sim­i­lar fea­tures.

Wrong base sta­tion. A net­work of iden­ti­cally named Wi-Fi routers with the same se­cu­rity set­tings lets you roam, whether in a mil­lion-square-foot of­fice tower or across rooms in your house. The de­vice you’re car­ry­ing, how­ever, doesn’t al­ways make the right choice about the strong­est sig­nal. In my small house, we have three base sta­tions due to thick walls. Lap­tops and mo­biles rou­tinely stay con­nected to a router in the base­ment when they’re within feet of one up­stairs. You can pick which base sta­tion to join when they’re all named the same, but cy­cling your Wi-Fi adap­tor from on to off to on typ­i­cally causes it to make a bet­ter choice.

Con­gested lo­cal net­work. If you’re at home or in an of­fice where you run the gear, you may be able to im­prove the Wi-Fi sit­u­a­tion around you. Out­side of mesh net­work­ing ecosys­tems, you can typ­i­cally con­nect to a Wi-Fi router and switch from the de­fault au­to­matic chan­nel as­sign­ment in each band to choos­ing a chan­nel. A lit­tle se­cret about Wi-Fi is that while the sig­nal lev­els have a sin­gle max­i­mum for all chan­nels in 2.4GHz, the 5GHz band is di­vided into three ma­jor pieces, and un­til 2014, each of them had a dif­fer­ent max­i­mum sig­nal limit. The low­est chan­nel

range (36, 40, 44, and 48) could only op­er­ate at no more than five per­cent of the max­i­mum of the high­est chan­nel range (149, 153, 157, and 161, typ­i­cally). Set­ting your 5GHz band to chan­nel 149 solves that if you have equip­ment that wasn’t re­vised to re­flect the new rules, which is the vast ma­jor­ity of base sta­tions that are at least two years old. (You can use a tool like WiFi Ex­plorer [$20, around £15, from fave.co/2BLcBlJ] to ex­am­ine what’s in use around you.)

One ex­tra tip: Force 5GHz. Many base sta­tions de­fault to nam­ing the sep­a­rate 2.4GHz and 5GHz net­works the

same to ease roam­ing. Most of them, how­ever, also let you choose a sep­a­rate name for each. If you want to en­sure the fastest con­nec­tion with the high­est sig­nal strength, hav­ing sep­a­rate 2.4GHz and 5GHz net­work names helps al­le­vi­ate the in­con­sis­tency you might ex­pe­ri­ence as a re­sult of con­nect­ing to the crowded 2.4GHz brand.

Cor­rect pass­word, no con­nec­tion

A net­work that re­quires ei­ther a pass­word or a user­name and pass­word will re­ject your de­vice if you en­ter it im­prop­erly. But what if you’re pos­i­tive you’re en­ter­ing the user­name and pass­word cor­rectly?

• Check whether you were given the pass­word with cor­rect cap­i­tal­iza­tion, which counts in Wi-Fi pass­words as in oth­ers. Spa­ces can be part of WPA2 passphrases, but spa­ces are hard to in­di­cate when writ­ten down. Con­firm you’re not miss­ing a space.

• Make sure you’ve se­lected the cor­rect net­work. In some places, you’ll be con­tend­ing with dozens or more sep­a­rately named net­works, and you may have se­lected one named sim­i­larly to the one you want. Some busi­nesses and hotspots run guest net­works named only slightly dif­fer­ently than their in­ter­nal, pri­vate net­works.

• Over­loaded net­works and routers with firmware that’s mal­func­tion­ing might re­ject a con­nec­tion, even when you’ve en­tered the pass­word prop­erly. Con­sult with the net­work’s man­ual – if that’s you, re­boot the router.

Your de­vice re­peat­edly re­joins the wrong net­work

Most mod­ern op­er­at­ing sys­tems re­tain a list of ev­ery net­work to which you’ve con­nected ever. My Mac has en­tries that date back sev­eral years across sev­eral ma­chine mi­gra­tions. Some ecosys­tems sync ac­cess, too, so when you join the net­work on one de­vice, all your other phones, tablets, and com­put­ers now can join with­out ad­di­tional ef­fort.

If you find a flaky net­work in a place you work or visit rou­tinely that you’ve joined once, you might have tried to for­get it, but it re­mains. I’ve seen this and heard from read­ers that delet­ing a net­work con­nec­tion doesn’t

fully re­move it, be­cause a synced copy else­where gets copied back to your de­vice! The trick is per­sis­tence: keep delet­ing it from ev­ery de­vice you’re us­ing so the sync­ing fi­nally syncs up.

You can man­age net­works in each op­er­at­ing sys­tem af­ter nav­i­gat­ing to these lo­ca­tions:

An­droid: Set­tings > Wi-Fi, tap the Cus­tom­ize but­ton and choose Saved Net­work.

iOS: In Set­tings > Wi-Fi, you can only for­get the cur­rently con­nected net­work.

Win­dows: Click the Net­work icon, choose Man­age WiFi Set­tings, and then choose Man­age Known Net­works.

macOS: Open the Net­work sys­tem pref­er­ence pane, click the Wi-Fi adap­tor in the list at left, click Ad­vanced, and then click the Wi-Fi tab.

Your adap­tor could just be dead

Wi-Fi adap­tors can just die, no mat­ter what kind of de­vice they’re em­bed­ded in. Be­fore giv­ing up, re­in­stalling the OS can be a fi­nal ditch way to see if it’s a cor­rupted driver rather than bro­ken hard­ware.

With a com­puter, you can pur­chase a cheap USB nub that plugs in and of­fers com­pat­i­ble ser­vice. With mo­bile phones and tablets, they may be un­re­pairable. As I was writ­ing this ar­ti­cle, a friend had just re­turned from the Ap­ple Store with a phone that had its Wi-Fi ac­cess go flaky and then fail: the store said it couldn’t be fixed, only re­placed.

The Wi-Fi Al­liance awards this logo to prod­ucts that meet its in­ter­op­er­abil­ity stan­dards, but its ab­sence on a prod­uct’s pack­ag­ing could just mean the man­u­fac­turer didn’t want to pay for the test­ing and cer­ti­fi­ca­tion

Some com­put­ers have but­tons that can turn the on board Wi-Fi adap­tor on and off

Check the IP ad­dress as­signed to your de­vice to en­sure that it has an ad­dress as­signed by your router

Speed-test tools like Ookla’s Speedtest.net can mea­sure the speed your broad­band ISP is pro­vid­ing, but you should test with a hard­wired con­nec­tion when­ever pos­si­ble

It’s al­ways a good idea to use a com­plex pass­word, but they can be dif­fi­cult to com­mu­ni­cate to oth­ers. Many mod­ern routers, in­clud­ing the Linksys Velop router shown here, let you share them via text mes­sage

Win­dows 10’s Man­age Known Net­works set­ting will show you ev­ery net­work your com­puter has ever joined (un­less you’ve told it to for­get some of them). If you know there are net­works you’ll never need to con­nect to again, click on each one and se­lect For­get

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.