Packages with the nis use flag

Global definition: Support for NIS/YP services.

mail-mta / exim : A highly configurable, drop-in replacement for sendmail

mail-mta / postfix : A fast and secure drop-in replacement for sendmail

mail-mta / sendmail : Widely-used Mail Transport Agent (MTA)

net-proxy / squid : A full-featured web proxy cache

sys-apps / net-tools : Standard Linux networking tools

sys-libs / pam : Linux-PAM (Pluggable Authentication Modules)