I have moodle set up on a linux box on the dmz zone of our firewall. I can login to it successfully from the server box itself, from another machine on the dmz zone, and using my laptop with a dialup connection to an internet ISP. However, using the same laptop (or other machines on our intranet) connected to the firewall trusted zone I cannot log in, either as Guest or a valid user. All that happens is that the login screen is returned. It does not show invalid logon messages if a non-existant user is specified. We use the same server for lots of other sites, and for example I can log in to phpAdmin on it from the intranet. It seems to be something to do with the firewall fitering but I'm not sure what.
Anyone any ideas what might be going on, or can they suggest further tests I might try?
I'll answer my own problem! It was the referrer info being stripped that was the cause of the problem, and Moodle was set to use secure forms. Next time I'll read the FAQ properly. (Thanks Martin for the FAQ I cant login - I just stay stuck on the login screen)