using Pidgin with CISCO Jabber

… because one can use FLOSS to chat, XMPP is an open standard, and an offical client is not available for GNU/Linux.

Step by Step

Prepare

• download Pidgin (if no recent versions are available for a given distribution, one can use flatpak)
• install openssl
• have a registered CUCM account and enable "Password for third-party XMPP clients" in TK-Portal¹.

Basics

• So which server do we have to talk to?
  From my experience, cucm-imp-1.itc.rwth-aachen.de does just fine for XMPP.

• Which login to use?
  The user id seems to be in the form lastName.institute@uc.rwth-aachen.de.
  A password can be set in the TK-Portal¹ with the option "Password for third-party XMPP clients".

The Certificate

Sadly, the server to which to connection is established, uses a self-signed certificate. Obviously, the client will complain about it. It is necessary to explicitly allow this cert.

$ openssl s_client -connect cucm-imp-1.pbx.rwth-aachen.de:5222 -starttls xmpp
CONNECTED(00000003)
depth=0 C = DE, O = RWTH Aachen, OU = IT Center, CN = cucm-imp-1-EC.pbx.rwth-aachen.de, ST = Nordrhein-Westfalen, L = Aachen
verify error:num=18:self signed certificate
verify return:1
depth=0 C = DE, O = RWTH Aachen, OU = IT Center, CN = cucm-imp-1-EC.pbx.rwth-aachen.de, ST = Nordrhein-Westfalen, L = Aachen
verify return:1
---
# [...]
Server certificate
-----BEGIN CERTIFICATE-----
# [...]
-----END CERTIFICATE-----
# [...]

The certificate can be copied from the output and saved to a file. Something like cucm-imp-1.pbx.rwth-aachen.de.pem.

In Pidgin, under > Tools > Certificates all stored certificates are shown and the new one can be added.

Adding an Account

In Pidgin, under > Accounts > Manage Accounts, a new account can be added:

• Tab Basics
  • Protocol: XMPP
  • Username: somthing in the form of lastName.institute should work (see "Basics" above)
  • Domain: uc.rwth-aachen.de
  • Resource (optional): a fancy name for the client as shown to XMPP contacts
  • Password: the password set in TK-Portal¹ (see "Basics" above)
• Tab Advanced
  • Connection security: Require encryption
  • Connect port: 5222
  • Connect server: cucm-imp-1.pbx.rwth-aachen.de

Now the account should be ready to use. Happyt chatting!

Additional Features

Join Group Chats

• Under > Tools > Plug-ins enable "XMPP Service Discovery".
• Open > Tools > XMPP Service Discovery > XMPP Service Discovery.
  • Press the "Browse" button.
  • Enter uc.rwth-aachen.de when asked "Select XMPP server to query" and press the "Find Services" button.
  • In the list there should appear some "conference-…" entries with the description "Text Conferencing"
  • Expand those entries and scroll trough the list of available group chats.
  • Double-clicking a group chat will open a dialog "Add Chat" to add this chat to ones account.
    • It might be necessary to enter a password here.
    • The process is completed by pressing the "Add" button.
• Now an existing group chat was added to the contact/chat list and can be accessed from there. (If the account is permitted to join.)

Creating Group Chats

• Open > Buddies > Add Chat.
  • Execute the service discovery as for joining a chat, to get available conference servers and check for used room named.
  • For the field Server choose one of the conference servers.
  • For the field Room choose an identifier not already taken.
  • Press the "Add" button.
• In the chat/contact list, navigate to the added room and double-click it.
  • A "Create New Room" promt should appear.
  • There one can either accept the defaults or proceed with customising the room settings (user limit, who can join, password, etc.).
• Now the room can be double-clicked again and a chat window should open.
  • Users can be invited using "> Conversation > Invite".

Be Aware

• This XMPP server does not support federated chatting and will refuse to talk to users on other XMPP servers, like jabber.rwth-aachen.de.
• This XMPP server does not store messages itself, only the local history is available.
• This is not an officially supported way of using the system! Use at your own risk!

Footnotes