Some time ago in 2024, while I was writing the Tops-20 Finger Server, Johnny and I collaborated on a finger specification for Finger over DECnet.  By 'collaborate', I mean I tried putting something together and Johnny pointed out the mistakes and things iterated from there.  It is hopefully better than an RFC.

The major difference from the Internet specification is that the protocol more closely aligns with a record orientated paradigm which is more appropriate for DECnet applications.  It can be told to do otherwise and stream large buffers, but the default is for the application to limit messages to line at time of no more than about 100 characters.  I don't remember if I ever publicly announced availability, but it can be found on VENTI2::DECNET-FINGER-SPECIFICATION.TXT for anonymous NFT.

The Tops-20 Finger server itself was effectively complete enough last year that I felt it appropriate to write a setup guide.  It can be read as a companion piece to the DECnet specification for more background information on how to implement the protocol.  

Further, and perhaps of more interest, it shows how to set up a network service on Tops-20 without Operator capability, which makes the server safer to run.  Think of not using Administrator (on Windows), root (on Ultrix), or SYS:, JACCT or [1,2] (on Tops-10) if you know what those are.  I don't know what the equivalent is on other DEC operating systems.  It can also be found on VENTI2::FNGSRV-SETUP.TXT.TXT for anonymous NFT.

If there are other DECnet finger clients on HECnet than Johnny's or mine, I would be delighted to hear about it.  It's pretty trivial; you open a connection to a remote host on object 117 (decimal) and send either a carriage return, a line feed (which gets you the default full system listing) or a user name followed by one of those two characters.  You then read responses and print them until the connection closes.  That's it.  That's all.

Maybe a one or two line Python program?  I could probably still do a trivial BLISS Common client, but I don't recall having learned the DECnet API for VMS.  At Marlboro, the little Bliss work that I did was for Tops-20 and Tops-10 and didn't do DECnet.  Supposedly, it would have been easy enough to run on VMS, but I never had the opportunity.

The only DECnet finger servers that are in full time production that I am aware of are running on MIM:: and VENTI2::.  TOMMYT:: runs it on an experimental basis, but requires a monitor upgrade and reconfiguration to do a full installation in order to go into production.  I'll do that later this year, I hope.