diff --git a/docs/add_net.md b/docs/add_net.md
index 7dd9b4c..2112ab3 100644
--- a/docs/add_net.md
+++ b/docs/add_net.md
@@ -82,3 +82,4 @@ IPv6, and VLAN ID.  Each can be visually compared to the others.)
  - [`add_v4_net`](add_v4_net.md)
  - [`add_v6_net`](add_v6_net.md)
  - [`add_vlan`](add_vlan.md)
+ - [`add_rtadv`](add_rtadv.md)
diff --git a/docs/add_rtadv.md b/docs/add_rtadv.md
new file mode 100644
index 0000000..1020c5e
--- /dev/null
+++ b/docs/add_rtadv.md
@@ -0,0 +1,38 @@
+# `add_rtadv` Command
+
+## Name
+
+`add_rtadv`
+
+## Synopsis
+
+```
+add_rtadv ${card} ${vlan}
+```
+
+## Description
+
+Adds the network defined by the specified `${card}` and `${vlan}` to the list of
+interfaces to be advertised by `rtadvd`.  
+
+The internal implementation prevents adding duplicate interfaces to the
+advertisement list, by checking for their presence before adding.
+It can safely be used alongside manual changes to `rc.conf` changes to
+the `rtadvd_interfaces` variable.
+
+Additionally, the `${rc_router_dir}/rc.d/generate_rtadvd_conf` service script
+will generate `${rc_router_gen_dir}/rtadvd.conf` with `${interface}:tc=settings`
+lines therein which can be used by the `rtadvd` that comes with FreeBSD.
+Various `rc.router` [variables](variables.md) can be used to control the global
+settings for all advertised IPv6 networks.
+
+## Examples
+
+```
+add_rtadv xy0 123 # Adds `xy0.123` to `rtadvd_interfaces`
+add_rtadv abc3 765 # Adds `abc3.765` to `rtadvd_interfaces`
+```
+
+## See Also
+ - [`add_net`](add_net.md)
+ - [`add_rtadv`](add_rtadv.md)
diff --git a/docs/add_vlan.md b/docs/add_vlan.md
index 14a66d4..82b1838 100644
--- a/docs/add_vlan.md
+++ b/docs/add_vlan.md
@@ -29,6 +29,7 @@ add_vlan abc3 765 # Creates abc3.765
 
 ## See Also
  - [`add_net`](add_net.md)
+ - [`add_rtadv`](add_rtadv.md)
  - [`add_v4_net`](add_v4_net.md)
  - [`add_v6_net`](add_v6_net.md)
  - [`clone_interface`](clone_interface.md)
diff --git a/docs/variables.md b/docs/variables.md
new file mode 100644
index 0000000..34afb8d
--- /dev/null
+++ b/docs/variables.md
@@ -0,0 +1,265 @@
+# `rc.router` Configuration Variables
+
+## `rc_router_ula_prefix_size`
+
+### Description
+
+Used to control the size of IPv6 ULA prefixes.  Can be either `48` or `56`
+
+### Example
+
+```
+rc_router_ula_prefix_size="48" # Generate `/48` IPv6 ULAs
+rc_router_ula_prefix_size="56" # Generate `/56` IPv6 ULAs
+```
+
+***
+
+## `rc_router_network_name`
+
+### Description
+
+A user-defined free-form string to provide sufficient "uniqueness" to generate ULA
+prefixes with sufficiently low probability of collision.  The user defined string
+permits a user to remember the uniqueness "seed" without having to remember 40
+or more random bits worth of hexidecimal digits.
+
+
+### Example
+
+```
+rc_router_network_name="This is my really awesome network!"
+```
+
+#### Note
+
+The `${secret_ip6_net}` undocumented variable can be used in `rc.d` scripts to
+expand to the user generated ULA prefix.  The name of this undocumented variable
+might change in the future.
+
+***
+
+## `v6_prefix_len`
+
+### Description
+
+This variable should only be set in ISP hints files.  It informs `rc.router` what
+IPv6 prefix size to request from that ISP.  Users may provide their own hints
+files in `${rc_router_conf_dir}/hints` -- hints files which are in the user
+configuration directory will override the pre-packaged hints.
+
+### Example
+
+```
+v6_prefix_len="63" # This ISP is pretty awful!
+v6_prefix_len="48" # This ISP is very generous.
+```
+
+***
+
+## `v4_net`
+
+### Description
+
+This variable defines a `/16` of IPv4 space inside which internal IPv4 networks
+are constructed.  In addition, `v4_net_${iface}` may be used to specify a `/16`
+prefix for all VLANs on a specific internal interface.
+
+### Example
+
+```
+v4_net="192.168" # This is pretty typical
+
+# Use a `/16` to differentiate the VLANs created on different physical interfaces.
+v4_net_xy1="172.21" 
+v4_net_xy2="172.22"
+```
+
+***
+
+## `rc_router_gen_dir`
+
+### Description
+
+This variable defines a director into which the configuration files for services
+will be generated.  By default it is `${rc_router_conf_dir}/gen`.
+
+### Example
+
+```
+rc_router_gen_dir="/tmp/rc-router-gen/"
+```
+
+***
+
+## `dhcpv4_pool_lo`
+
+### Description
+
+This variable defines the lower bound of DHCPv4 pools for auto-generated `/24`
+networks constructed by [`add_v4_net`](add_v4_net.md) or [`add_net`](add_net.md).
+These pools can also be specified per-physical-interface (but not vlan) by using
+`dhcpdv4_pool_lo_${iface}`.
+
+### Example
+
+```
+dhcpv4_pool_lo="10" # For most networks, start the dynamic pool at 10.
+dhcpv4_pool_lo_xy0="200" # For networks on `xy0`, start the dynamic pool at 200.
+```
+
+***
+
+## `dhcpv4_pool_hi`
+
+### Description
+
+This variable defines the upper bound of DHCPv4 pools for auto-generated `/24`
+networks constructed by [`add_v4_net`](add_v4_net.md) or [`add_net`](add_net.md).
+These pools can also be specified per-physical-interface (but not vlan) by using
+`dhcpdv4_pool_hi_${iface}`.
+
+### Example
+
+```
+dhcpv4_pool_hi="20" # For most networks, end the dynamic pool at 20.
+dhcpv4_pool_hi_xy0="240" # For networks on `xy0`, start the dynamic pool at 240.
+```
+
+
+***
+
+## `rtadvd_pltimedecr`
+
+### Description
+
+Controls whether the `pltimedecr` flag is set on generated router advertisement
+configuration files for IPv6.  Defaults to `NO`.
+
+### Example
+
+```
+rtadvd_pltimedecr="YES" # Enable `pltimedecr` in generated `rtadvd.conf` files.
+```
+
+***
+
+## `rtadvd_vltimedecr`
+
+### Description
+
+Controls whether the `vltimedecr` flag is set on generated router advertisement
+configuration files for IPv6.  Defaults to `NO`.
+
+### Example
+
+```
+rtadvd_vltimedecr="YES" # Enable `vltimedecr` in generated `rtadvd.conf` files.
+```
+
+***
+
+## `rtadvd_dns_search_list`
+
+### Description
+
+Allows the user to specify a list of search domain suffices to be delivered to
+all IPv6 clients.
+
+### Example
+
+```
+# Add the specified domains to the DNS search lists for `rtadvd`.
+rtadvd_dns_search_list="example.com local.example.com"
+```
+
+***
+
+## `rtadvd_pref64_prefix`
+
+### Description
+
+Allows the user to specify a NAT64 prefix for all networks advertised by
+`rtadvd`.  Note -- do not put the `/96` netmask suffix.  This is useful
+for building IPv6-only and IPv6-mostly networks that have to be compatible
+with legacy IPv4 destinations.
+
+### Example
+
+```
+# Add the specified domains to the DNS search lists for `rtadvd`.
+rtadvd_pref64_prefix="64:ff9b::"
+```
+
+***
+
+## `rtadvd_mininterval`
+
+### Description
+
+Allows the user to specify the minimum router advertisement interval.
+
+### Example
+
+```
+rtadvd_mininterval="300" # Advertise no more frequently than every 5 minutes.
+```
+
+***
+
+## `rtadvd_maxinterval`
+
+### Description
+
+Allows the user to specify the maximum router advertisement interval.
+
+### Example
+
+```
+rtadvd_maxinterval="1800" # Advertise less more frequently than every half hour.
+```
+
+***
+
+## `rtadvd_pltime`
+
+### Description
+
+Allows the user to specify the preferred lifetime for prefixes advertised by this
+router.
+
+### Example
+
+```
+rtadvd_pltime="300" # Advertise a preferred prefix lifetime of 5 minutes.
+```
+
+***
+
+## `rtadvd_vltime`
+
+### Description
+
+Allows the user to specify the valid lifetime for prefixes advertised by this
+router.
+
+### Example
+
+```
+rtadvd_vltime="900" # Advertise a valid prefix lifetime of 15 minutes.
+```
+
+***
+
+## `rtadvd_rltime`
+
+### Description
+
+Allows the user to specify the valid lifetime for the routing destination
+advertised by this router.
+
+### Example
+
+```
+rtadvd_rltime="900" # Advertise a router advertisement lifetime of 15 minutes.
+```