We now uses the no-addresses setting in krb5.conf on the acceptor side to check if the caddr field in an incoming service ticket matches the initiator's host address. According to available docs on krb5.conf, this setting is only used by the initiator side when requesting for the initial TGT.

http://www.daemon-systems.org/man/krb5.conf.5.html

    no-addresses = boolean
        When obtaining initial credentials, request them
        for an empty set of addresses, making the tickets
        valid from any address.

http://web.mit.edu/kerberos/krb5-1.4/krb5-1.4.1/doc/krb5-admin/libdefaults.html#libdefaults

    noaddresses
        Setting this flag causes the initial Kerberos ticket
        to be addressless. The default for the flag is set.