[strongSwan] how to tell charon-nm to use 500/udp and 4500/udp

Harald Dunkel harald.dunkel at aixigo.com
Thu Jul 14 15:46:46 CEST 2022

Hi folks,

is there some way to tell charon-nm to use 4500/udp for the outgoing
connection, instead of an arbitrary port, if available? Same for

I assume a problem on the AVM Fritzbox in this context. 500/udp and
4500/udp at both ends appears to be more reliable. However, I am not
sure at all where the temporary port comes from. I have just very
restricted access to the peer, since VPN is not working yet.



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