Which attribute is required for all IKE phase 2 negotiations？（）

单项选择题TwoVPNpeersarenegotiatingIKEphase1usingmainmode.Whichmessagepairinthenegotiation containsthephase1proposalforthepeers？（）

A.message 1 and 2
B.message 3 and 4
C.message 5 and 6
D.message 7 and 8

单项选择题WhichoperationalmodecommanddisplaysallactiveIPsecphase2securityassociations？（）

A.show ike security-associations
B.show ipsec security-associations
C.show security ike security-associations
D.show security ipsec security-associations

多项选择题RegardinganIPsecsecurityassociation（SA），whichtwostatementsaretrue？（）

A.IKE SA is bidirectional.
B.IPsec SA is bidirectional.
C.IKE SA is established during phase 2 negotiations.
D.IPsec SA is established during phase 2 negotiations.

多项选择题WhichtwoparametersareconfiguredinIPsecpolicy？（）

A.mode
B.IKE gateway
C.security proposal
D.Perfect Forward Secrecy

多项选择题WhichthreeparametersareconfiguredintheIKEpolicy？（）

A.mode
B.preshared key
C.external interface
D.security proposals
E.dead peer detection settings