The rlm_attr_filter module enables the attrs file.

Configuration

	# attr_filter - filters the attributes received in replies from
	# proxied servers, to make sure we send back to our RADIUS client
	# only allowed attributes.
	attr_filter attr_filter.post-proxy {
		attrsfile = ${confdir}/attrs
	}

	# attr_filter - filters the attributes in the packets we send to
	# the RADIUS home servers.
	attr_filter attr_filter.pre-proxy {
		attrsfile = ${confdir}/attrs.pre-proxy
	}