No GPL for managed software?

[list2010 at lunch.za.net]

Greetings,

A vendor (spamexperts.com) has given following response to a request to supply source code of the modified version of exim that is running on my employer's systems, which are managed by the vendor under contract:

    "I had things checked legally and since our company is fully managing / installing the software, we're actually not legally obliged to provide you these source modifications. Your are just supplying the hardware, we are fully managing the software. That's also clearly described in the contract."

Is this statement in harmony with the GPL copyright licence?  Is the content of the contract relevant?  

By way of context, the modifications to exim are to allow an encoded exim configuration (only machine readable), and some secret sauce in the way data is received (possibly for cluster support).  The question arose due to a production problem - there was a considerable backlog of mail due to high system load.  The regular fix for this is to run sendmail -q with a modified configuration file - but the configuration file was not available in a form which allowed modification, hence the request.  



(ps. the sender verification code as used by lists.gpl-violations.org and others does not implement SMTP time-outs correctly, and is redundant as well.)



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