In the packet radio days, our license conditions explicitly included this requirement. It was fulfilled by ordinary digipeating, but not by NET/ROM. I added support to my version of NET to make NET/ROM nodes operate as a virtual digipeater, so the outgoing connect of a NET/ROM on behalf of a user was not made under the USERCALL-(15-SSID) call, but as "user via node". (a packet that was transmitted by the node as if it had been digipeated by the node) IP was a problem under those regulations, however an arrangement was made with the authorities that source and destination of the traffic were sufficiently identified when there was an accessible list of IP addresses and corresponding callsigns. The hosts files provided that information. (I doubt that the authorities ever listened in on amateur IP over AX.25 traffic and tried to identify the endpoints, I heard that the only AX.25 equipment available at the monitoring station was a PK-232) However, since then we have lost our "license" and now operate under a "unlicensed station with mandatory registration" regime here, with usage conditions that are far less detailed. Operating modes are no longer specified, only identification modes. As long as you ID your station in one of a specified set of modes, they no longer care what you transmit and what its source is. This also makes it legal to forward internet content, something that was not allowed under our old license conditions (that explicitly prohibited 3rd party content and connections with external networks). But of course it can still be useful to have identification information in IPv6 addresses, if only because of the general lack of reverse-DNS information in the IPv6 network. Rob