IP Allow List

ip_allow_list drops UDP datagrams whose source address is not in the configured ranges. Use it before a terminal middleware such as dns or redirect to restrict which clients are served.

server:
  udp:
    middlewares:
      local_only:
        ip_allow_list:
          source_range:
            - 127.0.0.1/32
            - 10.0.0.0/8
    routers:
      dns:
        entrypoints:
          - dns
        middlewares:
          - local_only
          - resolver

Field	Description
source_range	List of allowed IPs or CIDR ranges. A datagram from any other source is dropped.

When the source address is not allowed the middleware returns an error, which stops the chain and drops the datagram before any response is sent.