LDAP groups not showing up (immediately)

Background: I use LDAP as a user storage for my unix machines holding all relevant user and group data in the directory. When I add a user to a group, only LDAP is changed.

Since I just stumbled across this issue and have been wondering what's wrong, here is a short reminder for next time:

Whenever you update groups in LDAP when using LDAP for users and groups you have to flush the nscd cache to see the new groups immediately. Use

nscd -i <tablename>

to do this.