Can anyone tell me what is configured on the server to enable or disable changing file permissions when using an ftp client? I know most servers allow changing file permissions via ftp, but a few allow it only via ssh or telnet. How is this done?

It'll be in your FTP daemons configuration file. Which FTP server and version are you running?

Thanks chirpy. I believe it's standard ftp on Solaris.

In reality, it's much more secure to disable FTP entirely. Passwords are sent in the clear, meaning if someone's intercepting your connection between you and the server, they could have enough information to hack your account.

Secure FTP (kinda like FTP over SSH) can be used instead. However, that isn't really practical most of the time, depending on how much experience you have with administration. SSH also has its own issues, but they are much different; most of the issues are either buffer overrun attacks of some kind or a fradulent customer who uses their SSH account to launch attacks from the server or gain root access.

As for your question though, I don't think that's a seperate thing that can be configured (at least on ProFTPd). Someone prove me wrong, please :)

No, you can in proftpd ;)

If you edit /etc/proftpd.conf and do the following:

If your version is lower than 1.2.4 add within (e.g.) the <Global></Global> directive:
AllowChmod off

If your version is equal to or higher than 1.2.4 add within (e.g.) the <Global></Global> directive:
<Limit SITE_CHMOD>
DenyAll
</Limit>

I'll give that a try... thanks!