Section 3.14.37. FramedGroupBaseAddress

3.14.37. FramedGroupBaseAddress

This optional parameter is used in conjunction with the Framed-Group reply attribute or the FramedGroup AuthBy parameter to automatically generate IP addresses for users logging in. It is ignored unless the user has a Framed-Group reply item, or unless their AuthBy clause contains a FramedGroup parameter. You can have as many FramedGroupBaseAddress items as you like.

You would only need to use this mechanism if you are using a NAS that is unable to choose IP addresses from an address pool, or if you want a more complicated address allocation policy than your NAS can support.

When a user logs in, Radiator can automatically choose an IP address for the user and return it to the NAS in a Framed-IP-Address reply attribute. To make this happen, you must specify one or more FramedGroupBaseAddress items in each Client clause, and you must specify a Framed-Group reply item for each user for whom you want address allocation. If the user is authenticated, Radiator will generate a Framed-IP-Address using Framed-Group reply item and the NAS-Port in the request. The Framed-Group in a user record selects the nth FramedGroupBaseAddress (0 based) from the Client they are logging in to, and NAS-Port is added to the last byte (modulo 255 or FramedGroupMaxPortsPerClassC) to generate a Framed-IP-Address.

Tip

Radiator also includes a much more sophisticated mechanism for allocating IP addresses from an SQL database or DHCP. For more information, see Section 3.56.

In the example below, if the user logs in on the Client at port 5, and their Framed-Group reply item is 1, they will be allocated a Framed-IP-Address of 10.0.1.6 (i.e. 10.0.1.1 + 5).

In the Radiator configuration file:

<Client ..>
      # This is the base address for Framed-Group = 0
      FramedGroupBaseAddress 10.0.0.1
      # This is the base address for Framed-Group = 1
      FramedGroupBaseAddress 10.0.1.1
      # This is the base address for Framed-Group = 2
      FramedGroupBaseAddress 10.0.2.1
      ....
</Client>

In the users file for each user you want to allocate an address for:

mikem       User-Password = "fred"
            Framed-Group = 1,
            Framed-Protocol = PPP,
            etc.

Alternatively, in an AuthBy clause:

<AuthBy whatever...>
      # This will cause all users authorised by this clause to get
      # an address allocated from the block starting 10.0.1.1,
      # unless overridden by a user-specific Framed-Group
      FramedGroup 1
      .....
</AuthBy>