Subject: Re: [OSPF] Suppression of frequent OSPF traps

From: Acee Lindem <[email-masked]>
Date: Thu, 7 Feb 2013 13:57:50 +0000

Sasha,
See inline.
On Feb 7, 2013, at 7:38 AM, Alexander Vainshtein wrote:

Dear all,
My colleagues and I are interested in interpretation of the following text from RFC 4750 - OSPF Version 2 Management Information Base<http://tools.ietf.org/html/rfc4750>:

     ospfIfConfigError NOTIFICATION-TYPE
          OBJECTS { ospfRouterId, -- The originator of the trap
             ospfIfIpAddress,
             ospfAddressLessIf,
             ospfPacketSrc,  -- The source IP address
             ospfConfigErrorType, -- Type of error
             ospfPacketType
             }
          STATUS       current
          DESCRIPTION
             "An ospfIfConfigError trap signifies that a
             packet has been received on a non-virtual
             interface from a router whose configuration
             parameters conflict with this router's
             configuration parameters.  Note that the event
             optionMismatch should cause a trap only if it
             prevents an adjacency from forming."
          ::= { ospfTraps 4 }

The highlighted text could be interpreted that the trap is sent every time an offending packet has been received.
This could easily result in an incessant flow of traps (e.g., if you receive offending Hello packets from a misconfigured router on the LAN segment).

Hence two  questions:
1.       Is the interpretation mentioned above valid?

Yes. If you don't have rate limiting for your traps, your SNMP implementation is broken. Furthermore, an implementation should be allow traps to be selectively enabled and disabled.
For example, here is the command from my implementation:

[local]se-acee(config-ctx)#router ospf 1
[local]se-acee(config-ospf)#snmp traps ?
  all                 Enable sending all supported OSPF traps
  ifauthfailure       Enable sending ospfIfAuthFailure traps
  ifconfigerror       Enable sending ospfIfConfigError traps
  ifrxbadpacket       Enable sending ospfIfRxBadPacket traps
  ifstatechange       Enable sending ospfIfStateChange traps
  maxagelsa           Enable sending ospfMaxAgeLsa traps
  nbrstatechange      Enable sending ospfNbrStateChange traps
  originatelsa        Enable sending ospfOriginateLsa traps
  txretransmit        Enable sending ospftxretransmit traps
  virtifauthfailure   Enable sending ospfVirtIfAuthFailure traps
  virtifconfigerror   Enable sending ospfVirtIfConfigError traps
  virtifrxbadpacket   Enable sending ospfVirtIfRxBadPacket traps
  virtifstatechange   Enable sending ospfIfVirtIfStateChange traps
  virtiftxretransmit  Enable sending ospfVirtIfTxRetransmit traps
  virtnbrstatechange  Enable sending ospfVirtNbrStateChange traps

Hope this helps,
Acee
P.S. If you really want to see some traps, enable ospfOriginateLas and ospfMaxAgeLsa on a core router.

2.       If not, what is the valid interpretation and associated expected behavior?

Regards, and lots of thanks in advance,
     Sasha

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