Network address translation

Tuesday 23 September 2003This is close to 20 years old. Be careful.

I’m a software geek, which means I’m perfectly happy to deal with hardware and icky things like wires as abstractions. The grungy details of how IP gets around are a perfect example. I don’t know, and for the most part, I don’t care. I have a home wireless network with a cable modem and firewall router. I put it together, but I just barely know how it works. I haven’t had to fiddle with it in over a year (knock wood).

Network Address Translation (NAT) is one of those network technologies I didn’t know much about. That’s changed, thanks to Charles Miller’s readable explanation of it all, complete with an assessment of why it’s flawed. I’ll be honest — I still don’t want to know all the details. I’m happy to leave those things to others who care and are fascinated by them. But now I know a little bit more, and that’s got to be a good thing.

BTW: I thought of titling this entry “NAT world”, but I decided that would be too cute and confusing.


This seems like an overblown indictment of NAT. It *does* have its uses, especially for in-home networks, where the idea is simply to have a multitude of client machines being able to share a single outward-facing IP address. The root of all of his angst seems to stem from server applications, which is -- to say the least -- an "advanced" topic for most broadband customers.

For the Ned and Andrew households, NAT does the job well with a bare minimum of fuss.
I admit it turned into a bit of a rant. But it's not really _that_ overblown. The problem is not server applications, it's P2P. To make a peer-to-peer connection, at least one side has to be un-NAT'd. (Unless you can piggyback on some intermediary)

So NAT really gets in the way of things like P2P (including IRC/IM) file-transfers, IP telephony and videoconferencing. I wouldn't call any of those things "advanced topics", they're more the sort of thing that a domestic user will either expect to "just work", or not use at all.
My mom, "Mrs. Average Broadband User", would call those "advanced topics". Yessir ee...

That being said, your point about P2P apps is taken.

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