Question
I administer an ejabberd server. I want to block file transferences, so my users cannot transfer files with anybody else. Is this possible in Jabber? Is this feature implemented in ejabberd?
Answer
There are several protocols for file transfer.
In general the Jabber clients negotiate the file tranference sending stanzas between both them, and those stanzas traverse their Jabber servers. The transference itself is performed directly between the two clients.
So, the Jabber server could intercept and drop the negotiation packets. Or return an error the the client.
However ejabberd doesn't implement such a blocking feature; and there isn't any known module that implements it.