Later versions of HTCondor should remove all of these limitations. -*: ENABLE_IPV6 must be specifed in your global HTCondor configuration file, not in one of you local configuration files (the ones specified with LOCAL_CONFIG_FILE or LOCAL_CONFIG_DIR). #3277 +*: ENABLE_IPV6 must be specifed in your global HTCondor configuration file, not in one of you local configuration files (the ones specified with LOCAL_CONFIG_FILE or LOCAL_CONFIG_DIR), nor using the environment variable _CONDOR_ENABLE_IPV6. #3277 *: Microsoft Windows is not supported. *: Mixed IPv4/IPv6 pools are not supported. *: Security policies cannot use IP addresses, only hostnames. (If you use NO_DNS=TRUE, the "hostnames" are reformatted IP addresses, and you can match against those.)