The GSS-API implementation in Heimdal implements the Kerberos 5 and the SPNEGO GSS-API security mechanisms.
Name/Page Description gss_accept_sec_context.3 gss_acquire_cred.3 gss_add_cred.3 gss_add_oid_set_member.3 gss_canonicalize_name.3 gss_compare_name.3 gss_context_time.3 gss_create_empty_oid_set.3 gss_delete_sec_context.3 gss_display_name.3 gss_display_status.3 gss_duplicate_name.3 gss_export_name.3 gss_export_sec_context.3 gss_get_mic.3 gss_import_name.3 gss_import_sec_context.3 gss_indicate_mechs.3 gss_init_sec_context.3 gss_inquire_context.3 gss_inquire_cred.3 gss_inquire_cred_by_mech.3 gss_inquire_mechs_for_name.3 gss_inquire_names_for_mech.3 gss_krb5_ccache_name.3 gss_krb5_compat_des3_mic.3 gss_krb5_copy_ccache.3 gss_krb5_extract_authz_data_from_sec_context.3 gss_krb5_import_ccache.3 gss_process_context_token.3 gss_release_buffer.3 gss_release_cred.3 gss_release_name.3 gss_release_oid_set.3 gss_seal.3 gss_sign.3 gss_test_oid_set_member.3 gss_unseal.3 gss_unwrap.3 gss_verify.3 gss_verify_mic.3 gss_wrap.3 gss_wrap_size_limit.3 Fi
New clients/servers will try both the old and new MIC in Heimdal 0.6. In 0.7 it will check only if configured - the compatibility code will be removed in 0.8.
Heimdal 0.6 still generates by default the broken GSS-API DES3 mic, this will change in 0.7 to generate correct des3 mic.
To turn on compatibility with older clients and servers, change the [gssapi] broken_des3_mic in krb5.conf that contains a list of globbing expressions that will be matched against the server name. To turn off generation of the old (incompatible) mic of the MIC use [gssapi] correct_des3_mic
If a match for a entry is in both [gssapi] correct_des3_mic and [gssapi] broken_des3_mic the later will override.
This config option modifies behaviour for both clients and servers.
Microsoft implemented SPNEGO to Windows2000, however, they manage to get it wrong, their implementation didn't fill in the MechListMIC in the reply token with the right content. There is a work around for this problem, but not all implementation support it.
Heimdal defaults to correct SPNEGO when the the kerberos implementation uses CFX, or when it is configured by the user. To turn on compatibility with peers, use option [gssapi] require_mechlist_mic
[gssapi] broken_des3_mic = cvs/*@SU.SE broken_des3_mic = host/*@E.KTH.SE correct_des3_mic = host/*@SU.SE require_mechlist_mic = host/*@SU.SE