Plugging a drive into my router gave me a free NAS. It also ruined my network

Published Oct 31, 2026, 2:30 PM EDT Arol is a tech journalist who currently works as a contributor at How-To Geek since 2022. He first began writing online for the short-lived portal of Spanish-language gaming forum Emudesc in 2013. Years later, in 2017, he got his true start in tech journalism working for a small Google-focused site called Pixel Spot. He transitioned to a news and feature writer role at XDA Developers that same year, where he worked until 2021 before making the jump to other websites. Arol brings nearly a decade of writing experience, and the occasional hot take, to his writings. While he's a technology lover at heart, he holds computer hardware and smartphones particularly close to heart. You'll normally find him covering news, although he has also written the occasional deal, buyer's guide, how-to post, and round-up. He's also written for Android Police and MakeUseOf. He's also a Political Science student at the Central University of Venezuela, and a proud member of student movement Àgora UCV. When he's not writing, you'll probably find him hitting the gym, trying to ace a new hobby, reading his textbooks, or traveling. You can reach him at me@arolwright.com. That USB port on the back of your router looks like an easy way to share storage at home, maybe even set up a full-blown NAS. It does work, for what it's worth. But the router has a different main job, and using it as a file server comes with costs most people don’t expect until their network slows down. Here's why that's a bad idea. The “Free NAS” option in your router A USB port and a menu toggle Most mid-range and high-end routers sold in the last decade include at least one USB port, and many manufacturers advertise it as a built-in storage feature. Netgear calls it ReadySHARE, ASUS bundles it under AiDisk and its USB application menu, and TP-Link lists it simply as USB Sharing. Everyone calls it differently. The names differ, but the idea is the same. You plug in a flash drive or an external hard drive, flip a switch in the router’s admin page, and the drive shows up as a shared folder for every device on your network. Under the hood, the router runs a small file server, usually Samba for SMB, the same protocol Windows uses for network folders. Many models also offer FTP access, a DLNA media server so smart TVs and consoles can browse your videos, and sometimes a remote access option that lets you reach the drive from outside your home. A few go further with basic download managers or Time Machine support for Macs. On paper, that is most of what an entry-level NAS box does, and you get it without buying anything new. There is no extra device drawing power, no operating system to install, and no separate configuration to learn. If you already own a spare external drive, the whole setup takes a few minutes. That convenience is why the feature is so tempting to use if you know about it. A dedicated NAS from Synology or QNAP costs a few hundred dollars before you add drives, and a home server built from a mini PC asks for time and some technical comfort. The router option asks for neither. It is already on, it is already connected to everything, and the port is right there. The trouble is that the hardware handling all of this was never designed to do it well. Why it’s a bad idea Your router can’t serve files and route traffic Credit: Bertel King / How-To Geek A router’s processor is built for one main task, which is moving packets between your devices and the internet. Much of that work is handed to dedicated networking hardware that does it efficiently without leaning on the main CPU. Serving files is different. When a device reads from or writes to the USB drive, the router’s general-purpose processor has to handle the file system, the Samba server, and the network transfer all at once, and consumer router chips are modest compared with even a cheap laptop. The result shows up in two ways. The first is speed. Transfers from a router-attached drive are typically far slower than the same drive connected directly to a computer, and TP-Link’s own support documentation acknowledges that USB performance depends on the router’s CPU and can fall below direct-connection speeds. Owners on enthusiast forums regularly report single-digit or low double-digit megabytes per second from drives capable of a hundred or more. The second effect is worse. During a large copy, the router’s CPU can sit near full load, and everything else on the network competes for what is left. Video streams buffer, game latency climbs, and video calls stutter, even on devices that have nothing to do with the file transfer. That is the moment a free NAS starts to feel expensive. Software support is another weak point to take into account. Router firmware gets updated slowly and is often abandoned after a few years. Several older models relied on SMBv1, a protocol Microsoft deprecated in 2014 and later stopped installing by default in Windows 10. Users of those routers were stuck choosing between turning a known-vulnerable protocol back on or losing access to their files. Finally, there is no protection for your data. A router-attached drive is a single disk with no redundancy, no health monitoring, and no automated backup. A power cut during a write can corrupt the file system, and if the drive fails, everything on it goes with it. Turning on remote access or FTP also exposes that drive to the internet through firmware that may not receive regular security patches. When you should do it Light, occasional use on a capable router Credit: Patrick Campanale / How-To Geek None of this means the USB port is useless. It means the feature fits a narrower set of jobs than the marketing suggests, and the closer your use stays to those jobs, the less you will notice the downsides. The best case is light, occasional access. Moving a handful of documents between a laptop and a desktop, keeping a shared folder of household paperwork, or giving a smart TV access to a small library of downloaded videos through DLNA are all reasonable. Streaming a single video file asks far less of the router than copying hundreds of gigabytes, and most modern routers handle it without dragging down the rest of the network. Your hardware matters too. A recent router with a quad-core processor, a USB 3.0 port, and firmware that supports SMB2 or SMB3 will do a much better job than an older dual-core model. If your router only supports SMBv1, the safest choice is to leave the feature off entirely rather than weaken security on every computer that connects to it. A few habits you can apply by yourself reduce the impact further. Use a wired connection when you move large batches of files, and schedule big transfers for times when nobody is gaming or on a video call. Keep remote access and FTP disabled unless you have a specific need and understand the exposure. Format the drive in a file system your router supports natively, and treat everything on it as a copy rather than the only version of anything important. If you find yourself depending on the drive daily, running backups to it, or wanting several people to stream from it at once, that is the sign you have outgrown it. At that point, a Raspberry Pi, a used mini PC, or an entry-level NAS will serve files faster and more safely, and your router can go back to doing its actual job. A router drive works for light sharing, not real backups Router USB storage is genuinely free and genuinely easy, but it borrows processing power your network needs. For occasional sharing and light streaming on a modern router, it works fine. For backups, heavy transfers, or anything irreplaceable, a dedicated device is the better choice.