Quantum cryptography could be integrated in various existing concepts and protocols to secure Metropolitan Area Networks communications. One of the possible use of quantum cryptography is within IPSEC. The applications of quantum cryptography are linked to telecommunication services that require very high level of security in Metropolitan Area Networks. The aim of this paper is to analyse the use of quantum cryptography within IPSEC to secure MAN communications and to present the estimated performances of this solution. We analyse classical IPSEC advantage and limits to point out how quantum cryptography could enhance the security level of IPSEC. After having introduced basic concepts in quantum cryptography, we propose a solution that integrate quantum key distribution into IPSEC. A performance analysis is done to demonstrate the operational feasibility of this solution.