Shielding for connector assembly

A receptacle connector assembly includes a contact module having signal contacts and ground contacts and a housing having a front shell and a rear shell coupled to the front shell. The front shell and the rear shell receive the signal contacts and corresponding header signal contacts of a header connector assembly in mating engagement with the signal contacts in a mating zone. The front shell and the rear shell receive the ground contacts and corresponding header ground contacts of the header connector assembly in mating engagement with the ground contacts in the mating zone. The rear shell has pockets receiving corresponding signal contacts and ground contacts. The rear shell has conductors at the front of the rear shell providing electrical shielding in the mating zone.