[Help-gnutls] Diffy-Hellman: Regeneration of prime and primitive root

[Martin Knappe]

Hi

I have seen source code examples of servers implementing Diffie Hellman and noticed that these often regenerate the prime and primitive root used to generate the shared secret. My questions:

1) Under what conditions is this necessary?
2) Why is this necessary?
3) How to find out the correct interval at which regeneration becomes necessary?

Hope someone here can help me...

Thanks

Martin