Recently while working on my homelab setup, I noticed the dual network ports on my NAS, and I got curious what was possible with the second. Looking through manuals and discussions, I learned I had a few options.
Many NAS devices these days, even some entry-level ones, include not just one but two network ports. This is despite the fact you only need one to connect it to the LAN. It's not there for nothing, though, and if you aren't taking advantage of it, you might be missing out.
Link aggregation for a better connection
The simplest and most common use for the second port on your NAS is link aggregation, sometimes called "trunking," "bonding," or "teaming." All it involves is using both ports to connect to your router, or another access point, with two different cables. This allows you to "aggregate" ports and take advantage of both at the same time.
How you set up link aggregation depends on your device, but you typically get several modes to choose from at configuration, like round robin, active backup, and adaptive load balancing. The mode for you depends on what you're trying to do with your NAS and what networking gear you have at your disposal, so you should read your NAS' manual on the topic.
The effect of most options though is better load balancing to increase reliability, plus the addition of fault tolerance. That means if one port fails for some reason, the other will automatically pick up the slack.
Link aggregation in general can improve your throughput. It won't be the doubling you might imagine, even if both ports give you the same maximum speed. Still, if you have an extra port on your router and an extra Ethernet cable that will reach it, there's virtually no reason not to take advantage of link aggregation on your NAS.
Wire in from a PC directly
If you're regularly moving files between your Wi-Fi-connected PC or laptop and your NAS, you can put your extra Ethernet port to use by connecting your PC directly to your NAS with a network cable. Obviously, you need a cable long enough to reach the NAS, but you also need to be prepared to manually adjust some network settings.
Specifically, you need to set a static IP address on your PC , and you also need to set a static IP on the NAS with an address on the same subnet as the PC. If you don't do this, the connection won't work.
The setup is worth it, though, if you want wired speeds without going through the router. I managed to do this with my NAS and my laptop. Over my Wi-Fi connection, I was maxing out at about 33MBs, averaging more like 20MBs. I was hitting a much better and more steady 105 to 110MBs with the direct line to the NAS.
Bridge a PC to the LAN (possibly)
Let's say you have a PC and a NAS in your office, but the office only has one network port. If you want a wired connection for both, the conventional answer is to get a network switch. However, it may be technically possible to give the one Ethernet connection to your NAS, then use the NAS' second port as a means to wire your PC into the wider network.
I could only find a few people on the internet successfully doing this, mostly on Synology devices. They were using "virtual switch" software installed on the NAS, which "bridges" the two ports to allow a secondary wired-in device (like your PC) to connect to the internet via the NAS as if it were a real network switch.
Most NAS devices are not designed for this function, though, and I'd recommend a hardware switch if you can manage it. Still, a bridge-over-NAS might be possible in a pinch. If you're going to attempt this, I recommend finding someone else who's done it before on your NAS and making sure you understand how virtual switch technology works.
While I was researching this topic, I noticed the RJ45 ports on the Uninterupted Power Supply (UPS) keeping my NAS powered and I wondered if they were an alternate route for my NAS' communication with the UPS. It turned out the answer was no; those ports were just for protecting the LAN from surges.
In fact, Ethernet-based communication with the UPS is only possible if your device is high-end enough to have an SNMP-enabled network card. Even then, you're probably going to be connecting it to the wider network rather than straight into the NAS, so that second port will still go unused.
If you're looking for other ways to get the most out of your NAS, learn how useful Portainer is on a NAS . If you don't own a NAS but are thinking about a purchase, consider building your own NAS device instead .
