aggregate(8) is a tool for aggregating CIDR networks. It understands IPv4 networks represented as network/prefix, network/netmask and start_address - end_address. It is able to read input in any one of these formats and output in the same or a different format. It is also able to limit the maximum and minimum prefix length that will be output, and thus can be used as a filter.
Perdition is a fully featured POP3 and IMAP4 proxy server. It is able to handle both SSL and non-SSL connections and redirect users to a real-server based on a database lookup. Perdition supports modular based database access. The distribution ships with modules for ODBC, MySQL, PostgreSQL, GDBM, POSIX Regular Expression, and NIS. The API for modules is open, allowing abitary modules to be written to allow access to any data store. Perdition can be used to create large mail systems where an end-user's mailbox may be stored on one of several hosts, to integrate different mail systems together, to migrate between different email infrastructures, and to bridge plain-text, SSL, and TLS services. It can also be used as part of a firewall.