Why is the list of services for NAT in a new router so ancient?
February 6, 2023 11:47 PM   Subscribe

So I just got switched over to fiber, and on setting up port forwarding on my new SMART/RG modem, I realized the list of preconfigured services was truly ancient: I don't think there was a single game or piece of software there that dated past 2001. I had had a similarly ancient list in my old DSL router, but I had assumed at the time that it was because it was so old itself. But why does a 2022 modem have a list of software two decades old? It was like looking at a time machine! KaZaA, Lotus Notes Server, Real Player 8...
posted by tavella to Computers & Internet (7 answers total)
 
The days of software requiring a set of ports to be manually opened are largely over, and with them, the need for a preconfigured list. So, no reason to update it.

I can't remember the last time I had to open ports. Nowadays, software either just uses standard ports e.g. 80 and 443, or automatically opens what it needs using UPnP.
posted by Klipspringer at 1:01 AM on February 7, 2023 [4 favorites]


Did you update the software yet? The basic boot image for embedded devices can be very basic indeed.
posted by Tell Me No Lies at 5:09 AM on February 7, 2023


Because whatever software is running in that machine is an archeological dig site, with layers and layers of code over whatever old code the project started with.

Somewhere in the source is a list of applications and related TCP ports and it just keeps getting handed down into the next project. Maybe it's edited to add newer stuff but nobody is brave enough to edit out older applications. Mostly because there is probably one customer out there that still needs Lotus Notes and will raise a massive stink if the router doesn't work. Storage of that list is essentially free anyway, so why mess with it?
posted by JoeZydeco at 7:45 AM on February 7, 2023 [1 favorite]


Wait until you see what’s still listed in /etc/services
posted by rd45 at 9:22 AM on February 7, 2023 [4 favorites]


Response by poster: The days of software requiring a set of ports to be manually opened are largely over, and with them, the need for a preconfigured list. So, no reason to update it.

I'm pretty sure that was post 2001, though? Again, I'm not surprised so much as very old things being listed as there being nothing newer than 2001. I would have thought that they would have removed the preconfigured feature sometime in the last 20 years if it was so totally unused. I will check about updating the router, though.
posted by tavella at 9:53 AM on February 7, 2023


I think it's a combo of what Klipspringer and JoeZydeco said: Lots of newer apps (that have enough userbase to matter) don't require you to manually configure ports. Also, there's a good chance that the router software is unloved and only minimally maintained.

If it were maintained I'd expect things like RealPlayer 8 to eventually get zapped from the list, even if newer apps don't need ports opened. It's likely just very old and crusty software.
posted by jzb at 11:29 AM on February 7, 2023


Old (or terrible) software required incoming ports to be opened temporarily. FTP is the classic example: it say to the server 'hey, I'm listening on my address at port X, call me!' and this fails abysmally with NAT. So you'd find protocol-aware NAT extensions that would listen to the control connection and forward the port being discussed.

This is nowadays considered a Really Bad Idea when designing protocols, partly because everybody has NAT at home that will screw up any new protocol designed this way, and partly because accepting incoming connections is just not a good plan. Modern (like, post 1994-ish, but it took a while to spread) FTP servers had a different way of doing this, and people eventually took note and avoided using inbound connections as they designed other protocols, so as time passed fewer and fewer special cases were needed.

So old protocols have the problem and need a special workaround in your NAT gateway; newer ones mostly don't.
posted by How much is that froggie in the window at 7:57 PM on February 7, 2023 [1 favorite]


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