When your internet is down and you call your ISP, what’s the usual answer you get? I’m willing to bet it’s either telling you to restart your router or telling you to wait. I’ve heard that one before; I’ve had my fair share of ISP troubles.
But your router might have a backup solution that you’re not even aware of, and your ISP would probably prefer if you didn’t know it, either.
Your router may already support two internet connections
Dual WAN is often hiding behind an ordinary LAN or USB port
Dual WAN lets one router connect to two separate internet sources at the same time. One connection usually comes from your regular modem or ISP gateway and acts as the primary WAN, while the second works as a backup.
This is fantastic if you have an unreliable ISP, because if the primary service goes down, the router can still keep you connected: it just moves your home network over to the secondary connection instead of leaving every device offline.
So, what do you need to make this whole thing happen? You don’t necessarily need a router with two WAN-labelled ports. On some models, an ordinary Ethernet LAN port can be reassigned as WAN2 through the router settings. Other routers may let you use a USB cellular modem, or even just a phone (which I do use as my backup internet quite a lot). You just need USB tethering for that.
The hardware may look like a standard home router, but the firmware may be doing all the work here, allowing you to essentially always have a connection to fall back on. But support varies considerably between routers, so chances are yours may not have it; having a second Ethernet or USB port does not guarantee dual WAN. As per usual, your best bet is digging into the spec sheet for answers. Look for stuff like Dual WAN, Multi-WAN, Secondary WAN, Link Backup, or Internet Failover.
Brand
eero
Wi-Fi Bands
Dual-band Wi-Fi 7
Amazon’s Eero 7 router gives you Wi-Fi 7 connectivity at a reasonable price point.
Failover is the dual-ISP mode most homes should use
Load balancing sounds faster, but it solves a different problem
Credit: Corbin Davenport / How-To Geek
Dual-WAN routers usually give you two ways to use those connections: failover and load balancing. Failover keeps your main ISP active and leaves the second connection waiting in the wings. If the router decides that your primary connection is down, it switches everything over to the backup.
This won’t be instant in many cases, but it’ll be better than waiting on a useless ISP to fix their internet, at least.
Once the main connection comes back, your router can just switch you back over automatically. For most homes, this is what makes sense.
Load balancing uses both internet connections at the same time, but don’t expect it to combine them into some kind of super-intense internet connection that’ll blow your mind. That’s not how it works. In most cases, the router simply spreads different devices or sessions across the two links. This is useful for a busy network, but you want failover if you just want a reliable backup.
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Your phone can take on the role of the second ISP
Cellular backup makes dual WAN useful without another full broadband plan
Credit: Goran Damnjanovic / How-To Geek
You don’t need a full-on second internet connection to make this work. I have one, because I’m paranoid and it’s cheap, plus I work exclusively from home, so internet outages are a serious pain. But paying for two separate home internet plans just in case one of them fails is definitely overkill, which I freely admit.
Fortunately, your backup connection can often just be a 4G or 5G modem, a mobile hotspot, or a phone connected over USB tethering. The router will treat that cellular connection like any other WAN source, so your existing Wi-Fi and wired devices can stay connected without each one joining the phone’s hotspot manually. (Not all routers support this, so your mileage may vary.)
Obviously, using mobile data has the usual limits; it’s not going to be anywhere near as good as your main connection most of the time.
Quiz8 Questions · Test Your Knowledge
DNS servers & how the internet finds its way
Trivia challenge
From 8.8.8.8 to how your browser finds cat videos — find out how much you really know about DNS.
DNS BasicsIP AddressesSecurityProvidersHistory
Begin
ADigital Network SecurityBDomain Name SystemCDistributed Node ServiceDDynamic Naming Standard
Correct! DNS stands for Domain Name System — the internet’s giant phone book that translates human-friendly domain names like ‘howtogeek.com’ into IP addresses computers can actually use. Without it, you’d need to memorize a string of numbers every time you wanted to visit a website.
Not quite — DNS stands for Domain Name System. It acts like the internet’s phone book, converting easy-to-remember domain names into the numerical IP addresses that computers use to route traffic. It’s one of the most fundamental building blocks of the modern web.
Continue
Before DNS was invented, how did computers resolve hostnames on the early internet (ARPANET)?
AEach router kept its own lookup tableBUsers typed IP addresses directly every timeCA single text file called HOSTS.TXT was downloaded from a central serverDA broadcast message was sent across the network asking for the address
That’s right! Before DNS, every computer on ARPANET relied on a file called HOSTS.TXT maintained by the Stanford Research Institute. Admins had to manually download the updated file to get new hostname mappings — not exactly scalable once the network started growing rapidly.
The answer is HOSTS.TXT. Before DNS existed, a single text file maintained at the Stanford Research Institute mapped all hostnames to addresses, and every machine had to download it periodically. As the internet grew, this system became completely unmanageable, which is exactly what motivated the creation of DNS in 1983.
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The famous DNS server at IP address 8.8.8.8 is operated by which company?
ACloudflareBOpenDNSCGoogleDMicrosoft
Correct! 8.8.8.8 (and its companion 8.8.4.4) is Google’s Public DNS service, launched in 2009. It was one of the first major free public DNS resolvers and became incredibly popular as a fast, reliable alternative to ISP-provided DNS servers.
The 8.8.8.8 address belongs to Google’s Public DNS, launched in 2009. Google made 8.8.8.8 easy to remember on purpose. Cloudflare runs 1.1.1.1, OpenDNS uses 208.67.222.222, and Microsoft’s Azure DNS exists but isn’t the same service — each provider pitches slightly different benefits like speed, privacy, or filtering.
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Cloudflare’s DNS resolver at 1.1.1.1 launched in 2018 with a strong emphasis on what selling point?
ABuilt-in ad blocking for all usersBUser privacy and not logging IP addressesCFaster speeds guaranteed by a global CDNDParental controls enabled by default
Spot on! Cloudflare launched 1.1.1.1 on April 1, 2018 (yes, really) with privacy as its headline feature, promising never to log users’ IP addresses or sell browsing data. It was independently audited by KPMG to back up those claims, which set it apart from many competitors.
Cloudflare’s big pitch for 1.1.1.1 was privacy — specifically the promise to never log users’ IP addresses or sell their data. While 1.1.1.1 is also very fast (often ranking #1 in independent speed tests), privacy was the headline claim at launch, backed by a third-party audit from KPMG. Ad blocking is available via a separate 1.1.1.2 address, but it’s not on by default.
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What is a DNS ‘resolver’ (also called a recursive resolver)?
AThe server that stores the original authoritative records for a domainBA piece of hardware inside your router that caches all domain names locallyCThe server that does the legwork of querying other DNS servers on your behalfDA security certificate that verifies a domain name is legitimate
Exactly right! A recursive resolver (like 8.8.8.8 or 1.1.1.1) is the middleman that takes your query and chases down the answer by contacting root servers, TLD servers, and authoritative nameservers — then delivers the final IP address back to you. It does all the heavy lifting so you don’t have to.
A recursive resolver is the server that does the legwork on your behalf — it contacts root nameservers, top-level domain servers, and authoritative nameservers in sequence until it finds the IP address you need. The authoritative nameserver is the one that actually holds the official records. Your resolver is essentially the internet’s investigator, tracking down answers one clue at a time.
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What type of attack involves poisoning a DNS cache with false records to redirect users to malicious websites?
ADNS spoofing (cache poisoning)BDDoS amplificationCBGP hijackingDARP flooding
Correct! DNS spoofing, also known as cache poisoning, tricks a DNS resolver into storing a fraudulent IP address for a legitimate domain. When users then request that domain, they’re silently redirected to a malicious server — which is exactly why DNSSEC was developed to cryptographically sign DNS records.
The attack you’re thinking of is DNS spoofing or cache poisoning. An attacker injects fake DNS records into a resolver’s cache, causing anyone who queries that resolver to be directed to the wrong — often malicious — IP address. DNSSEC (DNS Security Extensions) was designed specifically to fight this by adding cryptographic signatures to DNS records.
Continue
Which DNS record type is responsible for mapping a domain name to an IPv4 address?
AMX recordBCNAME recordCA recordDTXT record
Right on! The ‘A’ record (short for Address record) is the most fundamental DNS record type, mapping a hostname directly to a 32-bit IPv4 address. Its cousin, the AAAA record, does the same job for 128-bit IPv6 addresses — you’ll sometimes see both configured for the same domain.
The correct answer is the A record (Address record), which maps a domain to an IPv4 address. An MX record handles mail routing, a CNAME is an alias pointing one domain name to another, and TXT records store arbitrary text — often used for things like SPF email verification or domain ownership confirmation. The A record is the bread-and-butter of DNS.
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DNS-over-HTTPS (DoH) and DNS-over-TLS (DoT) both aim to solve the same core problem. What is it?
ADNS queries are too slow over long distancesBTraditional DNS queries are sent in plain text, making them visible to eavesdroppersCISPs charge extra for unencrypted DNS trafficDIPv6 addresses are too long for standard DNS packets to carry
Absolutely correct! Traditional DNS queries travel as plain, unencrypted text — meaning your ISP, network admin, or anyone monitoring traffic can see every domain you look up. DoH wraps DNS in HTTPS (using port 443), while DoT uses a dedicated TLS connection (port 853), both making your browsing queries much harder to snoop on.
The core problem that DoH and DoT solve is that standard DNS queries are completely unencrypted and readable by anyone watching your network traffic — your ISP, a coffee shop Wi-Fi operator, or a government. DNS-over-HTTPS hides queries inside normal HTTPS traffic, while DNS-over-TLS uses a dedicated encrypted channel. Both approaches protect your privacy at the DNS layer, which is surprisingly often overlooked.
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You need to configure and test failover before your internet goes down
Check it works before you bet on it
Credit: Nick Lewis / How-To Geek
To set this up, start by opening your router’s admin panel and looking under sections like WAN, Internet, Network, or Advanced Settings. The beauty of networking (and not the LinkedIn kind) is that every router has its own interface, so you may have to dig around a bit.
From there, look for Dual-WAN, Multi-WAN, Link Backup, or Failover. Set your usual broadband/fiber connection as the primary WAN and assign the second Ethernet port, USB modem, or tethered phone as the secondary one. Make sure you’re choosing failover rather than load balancing, and enable automatic failback if your router lets you.
Then, test, test, test. Disconnect the Ethernet cable running your main internet, and watch the router’s dashboard to see whether WAN2 takes over. Give it a minute, then try to load a few websites and see whether it works.
I speak from experience: Don’t rely on your ISP too much
I’ve had enough ISP-related problems to last me a lifetime, so I’m more cautious than most people. If you need to stay connected, dual-WAN failover is a good way to buy yourself some peace of mind without relying on (often unreliable) internet providers.