NAS-Port attribute question

Alan DeKok aland at
Mon May 7 14:15:07 CEST 2007

Muhammad Tayseer Alquoatli wrote:
> Hi list:
> I want your help to understand how freeradius uses NAS-Port attribute
> within rlm_ippool module
> I was looking for the interpretation of this attribute but i couldn't
> find more that "it's the physical port from which the request has
> come"

  Yes.  See your NAS documentation for more information about what it sends.

> reading the rlm_ippool code I've found that freeradius is using
> "NAS-IP, NAS-Port" pair as a key to search in the ippool file right ?
> so my questions are:
> 1- what does it mean with ("rlm_ippool: Searching for an entry for
> nas/port: %s/%u",key.nas,key.port)? does it mean that freeradius is
> searching for entries reserved by this nas/port ? and if this was true
> why it then set active entries to zero ? why it assume that this IP is
> not in use "i assume that active ip entry means it's in use"?

  No idea.  See the rlm_ippool code for more information.

> 2- regarding mppp, i assume that NAS-Port should be unique for all
> sessions other that mppp sessions. those mppp sessions must share the
> same NAS-Port. is this the right use of the NAS-Port attribute?

  Maybe.  See your NAS documentation for what it's sending, and when.

> 3- according to sum of my assumptions, all auth requests that will be
> handled by the same rlm_ippool instance and that all have the same
> NAS-IP, NAS-Port, CLI will certainly have the same ip address reserved
> for them in the post_auth section, and any change in the triple
> (nas-ip, nas-port, cli) will certainly cause them to have different ip
> address assignment. is this true? please correct me?

  That's the idea.

  Alan DeKok.
--       - The web site of the book - The blog

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