“Good day Valheimers! Todays patch has some huge changes to dedicated servers. Dedicated servers now always use direct connections instead of using Steam Datagram Relay (SDR). This should result in much lower latency for most players. Private dedicated servers are enabled by adding “-public 0″ to the server command line (See server manual PDF). You can only connect to private dedicated servers using the Join IP -button.”
Source: N4G PC Valheim 0.147.3 Patch Notes – Update makes huge changes to dedicated servers