Openwrt includes a firewall, but most wifi routers aren't fast enough to run complicated firewall rules, VPNs, etc. at full speed. If you want to set up complicated firewall rules or run a VPN server on the same machine as your firewall (you can always use a different server), AND you have a fast internet connection (like 1gbps) and want full speed then it's a good idea to use a faster x86 machine for the firewall. Lots of people just use openwrt and live with the performance penalty, though.
this post was submitted on 11 Aug 2023
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Openwrt includes a firewall, but most wifi routers aren’t fast enough to run complicated firewall rules, VPNs, etc. at full speed.
Not my experience. Right now I'm running 2 Wireguard VPNs and a moderately complex firewall on a single core 775Mhz Atheros TP-Link router and it's not even breaking a sweat. More than 60% of memory is available, and even when transferring a huge file the utilization doesn't exceed 50%.
Memory normally isn't the bottleneck. When you say "moderately complex firewall" does that include policy-based routing? What speeds do you get between a wireguard client and a wireless client?
PBR is in use and different LAN clients use different Wireguard VPNs or bypass the VPNs entirely. Download speeds are limited by remote server uplink speeds to about 100Mbps. Just ran a test and at full VPN utilization the router's loafing along at 22% CPU. No matter how complex I've made the config this cheap router has been able to easily handle it.
What VPN speeds were you running that maxed out your router CPU? Were you running Wireguard or OpenVPN?
I'm talking about 1gbps between multiple clients on LAN and VPN. I don't think there are any 802.11ax routers with a support that can handle gigabit speeds without any performance loss when you get the cpu involved in routing.
But I'm also saying most people will be fine with just an openwrt router. The features you get are usually worth the slight performance loss, and buying a separate firewall to squeeze an extra 100mbps out of your connection when you're already getting >850mbps doesn't always make sense.
In your response to the OP's question where you said "most wifi routers aren’t fast enough to run complicated firewall rules, VPNs, etc. at full speed" were you also "talking about 1gbps between multiple clients on LAN and VPN"?
OP: "use case: small home network 2-3 users. some internal self hosting and maybe one day external self hosting."
From their comments they don't even have a gigabit Internet connection, much less anything that would stress even a moderately priced router.
Openwrt isn't capable of providing enterprise level performance either but that's not what's being discussed. A high end router running Openwrt (and likely even cheaper hardware) should be able to handle OP's stated use case without breaking a sweat.
Yes, that's what I was talking about. And yes, OP has said in other comments that they have gigabit upstream. OP's original question was about why some people use openwrt as just an AP and use a separate machine for a firewall. I gave a common reason.
Personally, I'm building a NAS with 8 SAS drives controlled with an enterprise RAID controller and 2.5gbps ethernet. Total cost is under $300 (including drives) since it's all used hardware. Enterprises have moved past 1g/2.5g ethernet and SAS 2 a while ago, so lightly used hardware is cheap.
The best internet I could subscribe to where I’m at is 1024 Mbps down, 50 Mbps up. :(
Sounds like I can just use the router then.
1024Mbps = 1gbps
That's fast enough to hit the limit of most hardware people put openwrt on, but if you stick with standard firewall rules and don't install anything else on the router you should be ok. The router might limit your download speed slightly, but you should still easily get 800+ mbps.
ok, ok, I don't know how numbers work oops
I doubt the WAN would provide the advertised top theoretical speed most of the time; I just don't want to be running at like 10% of potential or something like that. If I were to do that I should at least get a cheaper plan.
You might see a 10% performance hit with gigabit internet depending on what you enable in openwrt and how fast your hardware is. On the other hand I wouldn't compare openwrt speed against the advertised speed. Test the actual speed you get by plugging your computer directly into your modem.
I mean I don't want to take a 90% performance hit lol. I can def live with 10% hit.
My bad. Yeah, you'll be fine. On the other hand, if you want to spend hundreds/thousands of $$ on network and server hardware, that's also an option ;)
TODO
Isn’t 1024 Mbps the same as 1 Gbps?
aaahh yes... you are right. I got the place values mixed up. ty :)
When I set up OpenWRT it had a firewall installed by default. I assume this is standard for all devices it can be installed on.
The firewall is the gatekeeper that typically controls the traffic between the WAN and LAN. Most routers have at least a basic firewall built in. Whether you should have a separate router and firewall depends on a few things.
A common scenario is if you're routing a whole bunch of different subnets internally. This is often the case in an enterprise environment where thousands of devices are connected to the network. Routing can eat up a lot of horsepower and you don't want spikes in WAN traffic slowing down your internal routing. In that situation it makes sense to have separate firewall and router appliances.
If you're running you're entire LAN on one subnet, you're not typically going to have any internal issues with routing related to WAN traffic. It's also easier to troubleshoot one network appliance than multiple. I run a single Mikrotik as my main router and firewall. Don't make it any more complex than you need to unless you just want to see if you can.
I run a single Mikrotik as my main router and firewall.
Cool! I also have a mikrotik. I flashed over the stock firmware in favour of openwrt which I have some experience with. And is free software.
Don’t make it any more complex than you need to unless you just want to see if you can.
I do not. I don't really enjoy networking stuff tbh. I am willing to do it because I think in the end I will be happier with the result. It's like going to the gym though.
A lot of forum posts are from people who are motivated by the learning value or by making small optimizations. I just want "good enough".
Is there any specific information about setting up the openwrt firewall that you'd recommend? Or is it literally included in the default install?
Check the firewall tap on openwrt. It should be set to sain defaults