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by LinuxBender 1986 days ago
I missed that part. I would not have expected that in Denmark. LSN is awful. You will be sharing source port depletion limitations with others in your network. That also means you can't host any servers unless you use port forwarding services or reverse vpns like hamachi. It also means you are sharing a SNAT with others on your network which means that malicious traffic from others could be attributed to you. Glad they are fixing it for you. If they didn't, then one would hope there were other ISP options.

Any ISP using LSN will have low NAT timeouts because it takes memory on their routers to track sessions and state. I would be surprised if your ISP remove timeouts unless they are letting it fall back to FIFO pruning on your segment. Did they tell you what they are changing?
2 comments
toast0 1986 days ago
It sounds like he's paid his ISP for a (dedicated) public IP, so it should be 1:1 NAT, which doesn't really need connection tracking.

For the rest of the customers that don't pay extra for a public IP, all the crappy things you mention do apply.

Hopefully, the ISP does native IPv6?

And, while 60 minute timeouts violate the RFC, it's a whole lot better than I expected. Usually CGN timeouts are around 15 minutes for nice ones, and I've seen 10 seconds at the bottom end.

I wish the longer ones would probe both ends of the connection to see if it's still live a minute or so before they intend to kill it.

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eznzt 1986 days ago
What you say sounds very dramatic, but the truth is that CGNAT is good enough for 99.9% of users.
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BlueTemplar 1985 days ago
That's bullshit, CGNAT is likely to cause all sorts of issues that the average users aren't going to realize being caused by their "I"SP (A frequent one : being unable to host video game sessions). They aren't getting real Internet, and are being treated as second tier citizens.
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arp242 1986 days ago
Yeah, my ISP uses it. It does come with some of the downsides the previous poster mentioned: the inability to make myself reachable from $the_world can be annoying, and I get a captcha on Google every time because of "unusual traffic" (I mostly use DDG, but sometimes fall back to it). Also, ACM blocked me at some point because "my IP is infiltrated by SciHub" (their words).

In the end, it's an imperfect solution for a real problem that mostly works well enough.

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