Warning: using default DH parameters

Ruby
1

Hello all,

I’m issuing HTTP requests via SSL, and the following warning is
reported:

c:/ruby/lib/ruby/1.8/net/http.rb:569: warning: using default DH
parameters.

This warning comes from the following line in net/http.rb:

    s = OpenSSL::SSL::SSLSocket.new(s, @ssl_context)

What is the meaning of this warning ? I assume that SSL complains about
the reduced cryptographic security because the parameters used for the
Diffie Hellman key exchange are default and not set by the applocation
?
So how can an application set these keys to avoid the warning ?