The thing is (I'm a mud administrator at avalon.mud.de) no one is using the telnet port for system administration any more, so MUDs startet redirecting port 23 to their gameport, so that players can just simply type: "telnet avalon.mud.de". It is mainly a usability thing.
If MUDs don't officially list port 23 then that could be because it's not their main port - or just a lazy legacy thing.
I can tell you that the major German MUDs allow connections over port 23, and I did a quick cross-check at an Iron Realm and I can connect over port 23.
For me this seems to be the largest common denominator, but I can understand if you want to recheck this on a greater basis. I thought it would be a nice little usability improvement for users.
I understand what you are saying, however for MUDs that are implemented on generic hired servers, they can't all be using port 23. So your suggestion would only be specific to MUDs where there is only one MUD on the server, and the admins don't use port 23 for administering the MUD (eg. by telnetting in to do compiles).
I am inclined to think that, if you advertise a MUD as being on <ip address> and <port> and the player has trouble understanding that level of detail, they will also have trouble understanding the quests, and the basic instructions that appear when they connect.
I don't think there's a single MUD host that would allow use of port 23. And even if they did, it would only be for one MUD out of all the MUDs hosted there.
Port 23 has become a sort of standard for a lot of muds to listen to, also due to the disuse of actual system maintenance through telnet.
Most people who start mudding, will tend to do so on a more publicized server. Simply because smaller ones do not get any exposure other than topmudsites/mudconnector, and that isn't where newbies to the genre come. A good number of muds has a java or flash client for people to use, and they tend to become insufficient for people because they're restrictive in normal stuff (resizing a window, changing a font, remembering certain simple settings, etc). So then they download a client.
Problem is, those people aren't stupid. Just not used to the concept of ports. In their webbrowser, port 80 is the standard. For ftp, 21. People never see ports. So for as far they know, all they need to do is type the server to connect to, and then they assume the default port is what they need. Then it doesn't, and they may do some research to actually figure out the connection information which holds the port. But a lot of newbies will check the address they typed and ignore the port, and give up because it doesn't work. Akin to pressing reconnect in their messenger or retyping user/pass if it doesn't work.
The fact is those people may be stellar roleplays, awesome at hack and slashes, but just like with cars where people know how to refill their gasoline, many won't know how to change their oil because it is either done by their garage or an acquaintance the one time it needs doing.
In my eyes, the default port should be the port that has the biggest chance of establishing a succesful connection, especially for the group who's newer to mudding (after all: once you're hooked you'll try a bit harder to solve your problems :D). Port 4000 can only be used by one mud at a time, so once there's more than one mud on a server (which might be a reason 23 isn't open) you still have to be specific. But 4000 isn't used by many muds at all in my experience, atleast not compared to 23.
Sure, port 23 is not advertised most of the time. But it is used for convenience. I bet that if you were to make a weighted graph with muds weighted depending on their average players, that port 23 would rank quite high. Non-port-23 muds would as a whole also rank quite high, and sure, in numbers they would probably swarm the use-port-23 muds, but the ones that do use 23 are quite likely to contain the biggest muds out there. As such, for the group with least know-how of ports , 23 would give a bigger successrate in connecting. (Someone should try to run such a test on all muds in the databases mentioned above, I'm curious now.)
I have done a quick check of about 500 MUDs on MudConnector (from their listing page). According to that, these are the port numbers in use (the number on the right is the number of times it is used):
Okay, seems my impressions were wrong then. :) Thanks for checking it out!
(Although I am still curious how things would look on a weighted list, where the amount of average players factors in to how heavy a mud weighs. I bet there's dozens of muds with a very small userbase, too.)
Listing > 70 MUDs acception port 23 connections. I don't know how this list is generated, but I see a lot of mainstream MUDs there.
As I said above the MUDs using 23 are not necessarily advertising it, since the idea was to open up 23 as an alternative to ease the (initial?) login for newbies. This list would not necessarily be complete.
As a large part (all?) of the bigger MUDs have adhered to this inofficial standard Mushclient could use this fact and make life this tiny bit easier for MUD-newbies. That was my idea.
As for administrating over port 23. I think we are all agreed that nobody _should_ be using this and going for ssh instead. But in 2008 I think we can also say for sure that nobody _is_ using it for that purpose.
Offtopic: Which MUDs are implemented in a way that more than one (official) MUD is accessible over the same IP? I have never encountered this before. If you don't mind my asking: Are these even relevant - usercount-wise? From the administrator perspective: I can't understand why a mud-admin should want that. It would be alike to having a webpage: www.domain.com/~myuser/ in a way: Really not well-suited for advertising ones MUD.
Checking out their web sites, as I expected, they are sites that host MUDs. Thus they have to allocate different ports to each MUD, as they are on the same server.
There may well be more, most MUDs are listed by a domain name, and it is possible they took out a domain name and redirected it to a MUD host service.