After upgrading to Junos OS release 16.1, systems that are configured for Subscriber Management may sometimes see the syslog message "bbe_if_ppp_input: Rx unknown packet protocol xxx code xxx on ifl pp0.xxx."

This article explains the nature of this message and whether any action must be taken after it is logged.

 

On an MX Series router that terminates Point-to-Point Protocol (PPP) subscribers, if the subscriber management daemon (bbe-smgd) that handles subscriber connections receives a packet that uses an unknown PPP protocol on the local pp0 interface, it will log a syslog message with the following syntax:

Jul  2 10:30:05 2018  MX960-re0 bbe=smgd[4822]: %DAEMON-3: bbe_if_ppp_input: Rx unknown packet protocol 0xfd80 code 0x1 on ifl pp0.3221978411

​This message was added in Junos OS release 16.1. Earlier versions of the software were designed to silently discard the packet.

 

In Junos OS release 16.1 and later, the MX BRAS added a default syslog message to be displayed if the subscriber management daemon received an unknown packet type. In earlier versions, however, the default behavior was to silently discard the packet.

In addition to the log message for unknown PPP protocols as already outlined above, the following logs related to PPP packets have also been added:

"%s: Rx LCP unknown packet code 0x%x on ifl %s.%u"
"%s: Rx PAP unknown packet code 0x%x on ifl %s.%u"
"%s: Rx CHAP unknown packet code 0x%x on ifl %s.%u"
"%s: Rx IPCP unknown packet code 0x%x on ifl %s.%u"
"%s: Rx IPv6CP unknown packet code 0x%x on ifl %s.%u"

 

These are informational messages to indicate packet drops, which would otherwise have been silently discarded. If there are no issues with subscriber connectivity or throughput, the messages can be ignored.

​To filter such messages from appearing, use the procedures outlined KB9382 - [Junos Platform] Example - How to prevent certain syslog messages from being written to the log file.