This program sends signed UDP packets to dynv6 to keep the port of SRV records up to date. It only works with ed25519 keys.
go get github.com/dynv6/srv-updater
If you don't have a ed25519 key, generate one:
openssh-keygen -t ed25519
The SRV updater uses raw sockets. Therefore It needs root privilege or CAP_NET_RAW capability.
-dst-host string
the destination host (default "dynv6.com")
-dst-port int
the destination port (default 55)
-fqdn string
the hostname of the record you want to update (default "_service._tcp.example.com")
-interval duration
sending interval (default 28s)
-key string
private key (default "~/.ssh/id_ed25519")
-priority uint
the priority of the record you want to update (default 10)
-src-ip string
the local ip address (default should be determined)
-src-port int
the local port (default 10000)
-weight uint
the weight of the record you want to update (default 1)
If the server does not understand the packet, it responds with a UDP packet containing an error message. You can read it with network protocol analyzers like tcpdump or wireshark.