packet_src_ip

Background

Most incoming RADIUS packets contains an attribute called NAS-IP-Address. This attribute is however not required as per the RFC since the incoming packet either has to contain NAS-IP-Address or NAS-Identifier, or both.

FreeRADIUS actually for the most part ignore this attribute (aside from using it when recording accounting data). FreeRADIUS has an internal (also called a meta) attribute called Packet-Src-IP-Address. This is the IP Address of the incoming UDP packet. It is used to compare against any clients that is defined in the clients.conf file (or in the nas table if you use sql).

So to summarise we have two important points:

• The incoming packet usually contains an AVP NAS-IP-Address.
• FreeRADIUS stores the IP Address of the incoming packet in the Packet-Src-IP-Address AVP. It does not use the value of NAS-IP-Address for this.

What can this result in?