Does concrete use any ports other than 80?

Hey, bit of a technical question:

I have submitted a really nice c5 website to a client for them to install it on their server. I am getting errors apparently surrounding the firewall on their server.

Has anyone run into problems with blocked ports and firewalls before? Here's what the IT there says:

"Now the situation is if you publish a static html page from Apache it is accessible from outside that means Firewall is pointing to web server correctly on port 80. But if I changed it to the index.php page that is your website it stop responding from out side the firwall. That is telling me your website trying to established connection on some other port/s other then 80. Do you have any idea about this?"

Anyone have any ideas?

View Replies:
Remo replied on at Permalink Reply
concrete5 tries to access some data by opening a connection on port 80 to other sites, like the rss block which pulls content from other sites.

But anything else is not related to concrete5. You can run concrete5 on port 234 if you want, it's just php which runs behind apache.

At least there isn't something I could imagine which would cause problems.. And I've got several clients with lots of firewalls..

But show us some links, error messages etc.