This router has no private options. Unless it is being used purely for verification (see verify_only) a transport is required to be defined by the generic transport option. The router accepts the address if its domain part takes the form of an RFC 2822 domain literal. For example, the ipliteral router handles the address
by setting up delivery to the host with that IP address. IPv4 domain literals
consist of an IPv4 address enclosed in square brackets. IPv6 domain literals
are similar, but the address is preceded by
ipv6:. For example:
ipv4: before IPv4 addresses, for consistency, and on the
grounds that sooner or later somebody will try it.
If the IP address matches something in ignore_target_hosts, the router declines. If an IP literal turns out to refer to the local host, the generic self option determines what happens.
The RFCs require support for domain literals; however, their use is controversial in today’s Internet. If you want to use this router, you must also set the main configuration option allow_domain_literals. Otherwise, Exim will not recognize the domain literal syntax in addresses.