"Usernames of 8 characters or less are recommended for compatibility with application software, but up to 16 characters are allowed."

[seanm]

Anyone know which software might have trouble with usernames > 8 characters? The User Guide says "Keeping usernames to eight characters or less is recommended for compatibility with legacy clients". How legacy are we talking about here? If all my clients are running an OS from the last 2 years, am I ok?

 

[garm]

Why on earth would you have a username longer then 8 characters?

 

[seanm]

Why on Earth wouldn't I? It's not 1970, my computer should be able to handle it. :)

But more seriously: plenty of people have surnames and/or given names that are > 8 characters. My LDAP directory currently has several "long" usernames, and that's working fine for *every* other service I run: postfix, dovecot, git, svn, wordpress, roundcube, etc. etc. etc.

 

[Redcoat]

From https://www.freebsd.org/cgi/man.cgi?query=adduser&sektion=8&manpath=freebsd-release-ports

RESTRICTIONS
username
Login name. The user name is restricted to whatever pw(8) will
accept. Generally this means it may contain only lowercase char-
acters or digits but cannot begin with the `-' character. Maxi-
mum length is 16 characters. The reasons for this limit are his-
torical. Given that people have traditionally wanted to break
this limit for aesthetic reasons, it has never been of great
importance to break such a basic fundamental parameter in UNIX.
You can change UT_NAMESIZE in <utmp.h> and recompile the world;
people have done this and it works, but you will have problems
with any precompiled programs, or source that assumes the 8-char-
acter name limit, such as NIS. The NIS protocol mandates an
8-character username. If you need a longer login name for e-mail
addresses, you can define an alias in /etc/mail/aliases.

 

[seanm]

Thanks Redcoat for the actual answer.

NIS, wow! Strange that 2019's FreeNAS still has this warning for a 1980s technology! :)

 

[anodos]

Thanks Redcoat for the actual answer.

NIS, wow! Strange that 2019's FreeNAS still has this warning for a 1980s technology! :)

That's because there are unfortunately still quite a few people using NIS (unfortunately).