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Possibly silly question: I was under the impression that only TCP allowed for NAT traversal; if I send a UDP packet to Google, how can Google respond without me
by portmanteaufu 12y ago
Possibly silly question: I was under the impression that only TCP allowed for NAT traversal; if I send a UDP packet to Google, how can Google respond without me configuring my router?
- wmf 12y agoNAT traversal is easier with UDP than with TCP. Here's a good article on the topic: https://www.zerotier.com/blog/?p=226 https://www.zerotier.com/blog/?p=226
- manigandham 12y agoThanks for posting, that was a nice article but the intro to ZeroTier was even better, pretty cool software.
- gliptic 12y agoNAT traversal isn't necessary when you send packets out of your network, be they TCP or UDP. That's standard operation for NATs.
- JoeAltmaier 12y agoHowever routers often have an 'allow UDP' checkbox. UDP can be globally disabled, or enabled only for certain ports. uPNP can mitigate this, but most of us have that turned off to prevent Trojan horses from opening the gates entirely.
- nomel 12y agoBigger question is, why in the world does your router disable UDP by default!? Things like games and video streams are almost universally UDP, because it's better to forget about the data than stop everything, and go get your lost packet.
- stephen_g 12y agoNot to mention DNS. Presumably the router would have a DNS caching server that could get around the block, but you wouldn't be able to have a computer use any other DNS server...