Just use this command to start the container. Unbound will listen on port 53/udp.

docker run --name unbound -d -p 53:53/udp -p 53:53 secns/unbound:1.5.9

(optional) If you want to override the nameserver in the unbound container, you can use:

docker run --name unbound -d -p 53:53/udp -p 53:53 --dns="127.0.0.1" secns/unbound:1.5.9

These options can be set via the environment variable -e flag:

• DO_IPV6: Enable or disable ipv6. (Default: "yes", Possible Values: "yes, no")
• DO_IPV4: Enable or disable ipv4. (Default: "yes", Possible Values: "yes, no")
• DO_UDP: Enable or disable udp. (Default: "yes", Possible Values: "yes, no")
• DO_TCP: Enable or disable tcp. (Default: "yes", Possible Values: "yes, no")
• VERBOSITY: Verbosity number, 0 is least verbose. (Default: "0", Possible Values: "")
• NUM_THREADS: Number of threads to create. 1 disables threading. (Default: "1", Possible Values: "")
• SO_RCVBUFF: Buffer size for UDP port 53 incoming. Use 4m to catch query spikes for busy servers. (Default: "0", Possible Values: "")
• SO_SNDBUF: Buffer size for UDP port 53 outgoing. Use 4m to handle spikes on very busy servers. (Default: "0", Possible Values: "")
• SO_REUSEPORT: Use SO_REUSEPORT to distribute queries over threads. (Default: "no", Possible Values: "yes, no")
• EDNS_BUFFER_SIZE: EDNS reassembly buffer to advertise to UDP peers. 1480 can solve fragmentation (timeouts). (Default: "4096", Possible Values: "")
• MSG_CACHE_SIZE: The amount of memory to use for the message cache. Plain value in bytes or you can append k, m or G. (Default: "4m", Possible Values: "")
• RRSET_CACHE_SIZE: The amount of memory to use for the RRset cache. Plain value in bytes or you can append k, m or G. (Default: "4m", Possible Values: "")
• CACHE_MIN_TTL: The time to live (TTL) value lower bound, in seconds. If more than an hour could easily give trouble due to stale data. (Default: "0", Possible Values: "")
• CACHE_MAX_TTL: The time to live (TTL) value cap for RRsets and messages in the cache. Items are not cached for longer. In seconds. (Default: "86400", Possible Values: "")
• CACHE_MAX_NEGATIVE_TTL: The time to live (TTL) value cap for negative responses in the cache. (Default: "3600", Possible Values: "")
• HIDE_IDENTITY: Enable to not answer id.server and hostname.bind queries. (Default: "no", Possible Values: "yes, no")
• HIDE_VERSION: Enable to not answer version.server and version.bind queries. (Default: "no", Possible Values: "yes, no")
• STATISTICS_INTERVAL: print statistics to the log (for every thread) every N seconds. (Default: "0", Possible Values: "0, 1")
• STATISTICS_CUMULATIVE: enable cumulative statistics, without clearing them after printing. (Default: "no", Possible Values: "yes, no")
• EXTENDED_STATISTICS: enable extended statistics (query types, answer codes, status) printed from unbound-control. (Default: "no", Possible Values: "yes, no")
• INTERFACE: Sets the interface to listen on useful when using --net=host (Default 0.0.0.0, Possible Values: "", "@")