I have an ejabberd 2.1.6 up and running with mod_auth_ldap, mod_shared_roster_ldap, mod_vcard_ldap with around 50 users, 20 through WAN.
Sometimes the ejabberd crashes my network and the server be totally inacessible through WAN, do not have heavy load of any resources: CPU, Memory, Bandwidth etc. But when stop or restart ejabberd, everything works fine.
