Unbound is a validating, recursive, and caching DNS resolver. Currently it’s only used only as DNS server for anti-spam DNSBL implementation.
When a new mail arrives, the anti-spam filter checks if sender IP address is listed in well-known blacklists. Some blacklists doesn’t allow multiple query from public DNS servers, thus the system needs a DNS server which can directly query the blacklist DNS.
If the mail filter is installed, dnsmasq configuration is changed, and specific
domain query are redirect trough unbond.
Configuration is saved in
unbound key inside
UDDPort: server address of the mail server, default is
access: default is
nonesince unbound should not be used as a normal DNS server
status: can be
disabled, default is
unbound=service UDPPort=10053 access=none status=enabled
Configuration can be applied using the