Here https://www.tinc-vpn.org/documentation/Example-configuration.html#Example-configuration you have: For Branch A BranchA would be configured like this: In /etc/tinc/company/tinc-up: # Real interface of internal network: # ifconfig eth0 10.1.54.1 netmask 255.255.0.0 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0 Is netmask 255.255.0.0 or 255.0.0.0 ? Thank you!