Where I work right now, they use a Nortel phone system. For voicemail, they use CallPilot. The CallPilot system happens to be on the network, which is rather intriguing. For the department I am in, we use an Asterisk phone system that talks to the Nortel. I’ve always wondered however if there was an phone directory of the extensions. I was told no. So I did some digging. I happened across and LDAP server running on the CallPilot system. After some hacking, I discovered that the LDAP system had all the names in it (outdated of course). Two caveats though: it is only the extensions which have voicemail and it is using LDAP 2.0.