podman/docs/source/markdown/options/network.image.md

####> This option file is used in: ####> podman build, farm build ####> If file is edited, make sure the changes ####> are applicable to all of those.

--network=mode, --net

Sets the configuration for network namespaces when handling RUN instructions.

Valid mode values are:

• none: no networking.
• host: use the Podman host network stack. Note: the host mode gives the container full access to local system services such as D-bus and is therefore considered insecure.
• ns:path: path to a network namespace to join.
• private: create a new namespace for the container (default)
• <network name|ID>: Join the network with the given name or ID, e.g. use --network mynet to join the network with the name mynet. Only supported for rootful users.
• slirp4netns[:OPTIONS,...]: use slirp4netns(1) to create a user network stack. It is possible to specify these additional options, they can also be set with network_cmd_options in containers.conf:
  • allow_host_loopback=true|false: Allow slirp4netns to reach the host loopback IP (default is 10.0.2.2 or the second IP from slirp4netns cidr subnet when changed, see the cidr option below). The default is false.
  • mtu=MTU: Specify the MTU to use for this network. (Default is 65520).
  • cidr=CIDR: Specify ip range to use for this network. (Default is 10.0.2.0/24).
  • enable_ipv6=true|false: Enable IPv6. Default is true. (Required for outbound_addr6).
  • outbound_addr=INTERFACE: Specify the outbound interface slirp binds to (ipv4 traffic only).
  • outbound_addr=IPv4: Specify the outbound ipv4 address slirp binds to.
  • outbound_addr6=INTERFACE: Specify the outbound interface slirp binds to (ipv6 traffic only).
  • outbound_addr6=IPv6: Specify the outbound ipv6 address slirp binds to.
• pasta[:OPTIONS,...]: use pasta(1) to create a user-mode networking stack.
  This is the default for rootless containers and only supported in rootless mode.
  By default, IPv4 and IPv6 addresses and routes, as well as the pod interface name, are copied from the host. If port forwarding isn't configured, ports are forwarded dynamically as services are bound on either side (init namespace or container namespace). Port forwarding preserves the original source IP address. Options described in pasta(1) can be specified as comma-separated arguments.
  In terms of pasta(1) options, --config-net is given by default, in order to configure networking when the container is started, and --no-map-gw is also assumed by default, to avoid direct access from container to host using the gateway address. The latter can be overridden by passing --map-gw in the pasta-specific options (despite not being an actual pasta(1) option).
  Also, -t none and -u none are passed to disable automatic port forwarding based on bound ports. Similarly, -T none and -U none are given to disable the same functionality from container to host.
  Some examples:
  • pasta:--map-gw: Allow the container to directly reach the host using the gateway address.
  • pasta:--mtu,1500: Specify a 1500 bytes MTU for the tap interface in the container.
  • pasta:--ipv4-only,-a,10.0.2.0,-n,24,-g,10.0.2.2,--dns-forward,10.0.2.3,-m,1500,--no-ndp,--no-dhcpv6,--no-dhcp, equivalent to default slirp4netns(1) options: disable IPv6, assign 10.0.2.0/24 to the tap0 interface in the container, with gateway 10.0.2.3, enable DNS forwarder reachable at 10.0.2.3, set MTU to 1500 bytes, disable NDP, DHCPv6 and DHCP support.
  • pasta:-I,tap0,--ipv4-only,-a,10.0.2.0,-n,24,-g,10.0.2.2,--dns-forward,10.0.2.3,--no-ndp,--no-dhcpv6,--no-dhcp, equivalent to default slirp4netns(1) options with Podman overrides: same as above, but leave the MTU to 65520 bytes
  • pasta:-t,auto,-u,auto,-T,auto,-U,auto: enable automatic port forwarding based on observed bound ports from both host and container sides
  • pasta:-T,5201: enable forwarding of TCP port 5201 from container to host, using the loopback interface instead of the tap interface for improved performance