SNMP Support
************

SNMP (Simple Network Managing Protocol) is a widely implemented feature for collecting network information from router and/or host. Quagga itself does not support SNMP agent (server daemon) functionality but is able to connect to a SNMP agent using the SMUX protocol (RFC1227) and make the routing protocol MIBs available through it.

Getting and installing an SNMP agent
====================================

There are several SNMP agent which support SMUX. We recommend to use the latest version of net-snmp which was formerly known as ucd-snmp. It is free and open software and available at http://www.net-snmp.org/ and as binary package for most Linux distributions. net-snmp has to be compiled with --with-mib-modules=smux to be able to accept connections from Quagga.

SMUX configuration
==================

To enable SMUX protocol support, Quagga must have been build with the --enable-snmp option.

A separate connection has then to be established between between the SNMP agent (snmpd) and each of the Quagga daemons. This connections each use different OID numbers and passwords. Be aware that this OID number is not the one that is used in queries by clients, it is solely used for the intercommunication of the daemons.

In the following example the ospfd daemon will be connected to the snmpd daemon using the password "quagga_ospfd". For testing it is recommending to take exactly the below snmpd.conf as wrong access restrictions can be hard to debug.

     /etc/snmp/snmpd.conf:
     	#
     	# example access restrictions setup
     	#
     	com2sec readonly default public
     	group MyROGroup v1 readonly
     	view all included .1 80
     	access MyROGroup "" any noauth exact all none none
     	#
     	# the following line is relevant for Quagga
     	#
     	smuxpeer .1.3.6.1.4.1.3317.1.2.5 quagga_ospfd

     /etc/quagga/ospf:
     	! ... the rest of ospfd.conf has been omitted for clarity ...
     	!
     	smux peer .1.3.6.1.4.1.3317.1.2.5 quagga_ospfd
     	!

After restarting snmpd and quagga, a successful connection can be verified in the syslog and by querying the SNMP daemon:

     snmpd[12300]: [smux_accept] accepted fd 12 from 127.0.0.1:36255
     snmpd[12300]: accepted smux peer: \
     	oid GNOME-PRODUCT-ZEBRA-MIB::ospfd, quagga-0.96.5

     # snmpwalk -c public -v1 localhost .1.3.6.1.2.1.14.1.1
     OSPF-MIB::ospfRouterId.0 = IpAddress: 192.168.42.109

Be warned that the current version (5.1.1) of the Net-SNMP daemon writes a line for every SNMP connect to the syslog which can lead to enormous log file sizes. If that is a problem you should consider to patch snmpd and comment out the troublesome snmp_log() line in the function netsnmp_agent_check_packet() in agent/snmp_agent.c.

MIB and command reference
=========================

The following OID numbers are used for the interprocess communication of snmpd and the Quagga daemons. Sadly, SNMP has not been implemented in all daemons yet.

                 (OIDs below .iso.org.dod.internet.private.enterprises)
     zebra .1.3.6.1.4.1.3317.1.2.1 .gnome.gnomeProducts.zebra.zserv
     bgpd  .1.3.6.1.4.1.3317.1.2.2 .gnome.gnomeProducts.zebra.bgpd
     ripd  .1.3.6.1.4.1.3317.1.2.3 .gnome.gnomeProducts.zebra.ripd
     ospfd .1.3.6.1.4.1.3317.1.2.5 .gnome.gnomeProducts.zebra.ospfd

The following OID numbers are used for querying the SNMP daemon by a client:

     zebra .1,3,6,1,2,1,4,24  .iso.org.dot.internet.mgmt.mib-2.ip.ipForward
     ospfd .1.3.6.1.2.1.14    .iso.org.dot.internet.mgmt.mib-2.ospf
     bgpd  .1.3.6.1.2.1.15    .iso.org.dot.internet.mgmt.mib-2.bgp
     ripd  .1.3.6.1.2.1.23    .iso.org.dot.internet.mgmt.mib-2.rip2

The following syntax is understood by the Quagga daemons for configuring SNMP:
 -- Command: smux peer OID
 -- Command: no smux peer OID

 -- Command: smux peer OID PASSWORD
 -- Command: no smux peer OID PASSWORD