pam_ihosts is a PAM module that can allow/deny login on the basis of IP address, MAC address or the country-code/registrar associated with an IP. It uses the allocated ip-range files that are downloadable from Regional Internet Registries. pam_ihosts can also check in whitelist/blacklist files and in DNS whitelists/blacklists.
Inadyn is a small and simple DDNS client with HTTPS support, both GnuTLS and OpenSSL are supported. Inadyn is commonly available in many GNU/Linux distributions, used in off-the-shelf routers and Internet gateways to automate the task of keeping your DNS record up to date with any IP address changes from your ISP. It can also be used in installations with redundant (backup) connections to the Internet.
DomDNS is a Web DNS management service to create records in DNS servers, in multiples zones, with view support. Supports REST for all actions. It allow the zones to be managed or just seen by users. The interface is in English or in French. The zones or the records can be enable/disable on time basis.
Dowse is a transparent proxy facilitating the awareness of ingoing and outgoing connections, from, to, and within a local area network. Dowse provides a central point of soft control for all local traffic: from ARP traffic (layer 2) to TCP/IP (layers 3 and 4) as well as application space, by chaining a firewall setup to a trasparent proxy setup. A core feature for Dowse is that of hiding all the complexity of such a setup.
Admin4 is a broad server management tool. It has plugins for maintaining LDAP directories, BIND DNS zones, IMAP servers and PostgreSQL databases. It's a Python and wxWidgets control center, for customization and easier addition of new plugins.
Knot DNS is a high performance authoritative-only DNS server. It supports all key features of the domain name system including zone transfers, dynamic updates, and DNSSEC.