License of developed site

First of all I apologize if this question is already answered, but I haven’t been able to find any answer of it. We want to develop a new website based on Community Builder for a customer, with some modifications. The customer will use it in their servers but will not redistribute the software, he will use it only for the website, so it will be public in some way.
Community Builder is GPL and is based on Joomla that is also GPL, so any modification should be also GPL. There is obligation to provide the source code to any distributed software.
However what happened when the software is not distributed, only executed on a server withh public access? Is it considered public and then our customer will be obliged to provide the source code?.
I am sorry but I could not be able to find any answer to this questions, only that the GLP V3 and GPL affero includes the requirement to deliver source code also for software used in web servers.
The answer is critical for us becuase the customer is really concern about the possible consequences.

Thanks in advance

Hi and thanks for posting.

Please note that I am in not by any means qualified to provide legal assistance of this nature - as your question is a legal one.

I have an opinion but as I am not an expert I do not think it is appropriate to mislead you in any way.

Suggest posting your question on some legal forum board to get qualified answers.