My elder kid was assay to enforce for college at a university in Florida . Perversely , its website refused to appear . He tried Safari , Firefox , and Chrome on his Mac and Safari on his iPhone . Only his devices appeared to be move . Switching to cellular run , isolate the job to our local connection . Yet my Mac laptop computer could reach the site just hunky-dory . Reviewing our router and other setting , I could n’t find a grounds for this failure .
What I eventually discovered ? Our primary web and Wi - Fi router had outdated DNS server information . Our provider , CenturyLink , had at some detail update the waiter it uses to provide knowledge domain name system ( DNS ) disc lookups . When you type in something likepodunk.edu , your operating system has to perform a DNS query to convert that address into a machine figure ( an IP ( Internet Protocol ) address ) that it expend to produce the real terminal - to - last connection between a web internet browser or other computer software and a host .
DNS servers are unloved bits of public utility . In the tardy 2000s , many ISPs had overlooked the speeding of these servers , which may perform 1000000000000 of simple queries a day or more for a meshing of users . A slow DNS lookup could make everything on your gadget sluggish as you browse around . ( The information is cached for minutes to Day , so the first lookup is the afflictive one . )
Some third party grow on the back of providing high - quality freemium DNS lookups : super - fast responses for costless , and you could ante up extra for filtering and other service . Eventually , Google set out into the business organisation withPublic DNS , a free service uncouple from ISPs . Others followed .
On most home networks , your ISP provides you details to put down manually into your router apparatus to bootstrap access code . This almost always includes the IP savoir-faire of two DNS servers – primary and secondary – which you have to come in in numeral form . It ’s a chicken - and - egg job : you ca n’t use DNS to look up a name if your net or devices do n’t recognise how to find a DNS server . You may never have to deepen those details . Some mass in the last X - plus have deepen those configurations to point to Google other free or paid DNS services .
When you connect a Mac , iPhone , or other net - capable hardware to a local web via Wi - Fi or ethernet , intimately all home electronic connection automatically impute it a local electronic connection address . That grant points your equipment ’s DNS requests to the router , which in turn relays them to the DNS servers it has configured in its preferences .
In my case , CenturyLink is our provider , and I in all likelihood had n’t alter our DNS server numbers for as long as I can think . But on my Mac laptop , I have mess up with them at multiplication just for that computer , for examination and for speed . ( Go toSystem Preferences > internet , selectWi - Fi , clickAdvanced , clickDNS , and click the + at the bottom - left corner to add one or more custom entranceway . ) These tradition entree override the DNS host info at the router level in favor of the one you pick .
At this compass point , I had a hunch . Had CenturyLink change its DNS server address without , say , notifying its client ? sure as shooting enough , CenturyLink ’s help pageboy on DNS host addressesshowed ones I had n’t seen before and were n’t set up on my router . I updated my router options , applied them , and suddenly the “ crushed ” university pageboy loaded fine on all our networked gadget .
The only mystery remain is how CenturyLink is running a semi - confused DNS former server that seemed to omit onlyonesite on the cyberspace .
We also have advice aboutwhat to do if your Wi - Fi is n’t working on an iPhoneandhow to secure Wi - Fi on a Mac , andhow to improve Wi - Fi signal .
This Mac 911 article is in reply to a dubiousness subject by Macworld lector Benjamin .
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