Port mapping on your router / Discovery Failture

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Does Syncthing attempt to install port mapping on routers upon install, or does it detect and try to add on each startup? I’m asking because I accidentally deleted the mapping and I think that’s the reason why Global Discoveries stopped working; everything syncs on the local network but not outside, and I have the following Discovery Failures on all my devices:

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I’m under the impression that when NAT Traversal is turned on, Syncthing tries to punch the hole on startup. I’m not 100% on that.

Global Discovery does not use NAT Traversal.

Is it possible that your router took your deletion of the NAT Traversal as an instruction to block the host?

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This is an IPv6-only discovery server. If you don’t have IPv6 connectivity it is expected for connections to it to fail.

In this case it is a DNS resolution error, not a connection error, which could happen if your DNS server is blocking AAAA lookups.

Posting to discovery doesn’t require any explicit portmappings for the same reason that visiting the Syncthing forum doesn’t require any explicit portmappings; it’s an outgoing connection.

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