[j-nsp] What does AS path attribute problem mean?

[Juniper GOWEX]

Hi Experts,

The attributes problems have appearedagain:

        /Sep 19 20:46:43 router1.net LEV[2625]: bgp_path_attr_error: NOTIFICATION sent to 149.X.X.X (External AS XXX): code 3 (Update Message Error) subcode 11 (AS path attribute problem)/



and looking at the Juniper KB I found a workaround :


        /"In order to stop the BGP session flaps, a per-neighbor
        configuration option exists that will cause JUNOSe to ignore any
        illegal or incorrectly formatted attributes:
        /

            /ERX(config)#*router bgp*//<AS#>
            ERX(config-router)#*neighbor*//<x.x.x.x>*  lenient*/

        /Provided log category |*bgpMessages*| has been set to log
        severity warning by configuring:
        /

            /ERX(config)#*log severity warning bgpMessages*/

        /a message will still be logged when an illegal attribute is
        received:

        |WARNING 01/01/2008 19:34:52 bgpMessages (default,10.0.0.2):
        UPDATE message from peer 10.0.0.2 in core: new-as-path contains
        segment type confed-sequence (not allowed). "|
        /

http://kb.juniper.net/InfoCenter/index?page=content&id=KB13623&actp=RSS



Does anyone know or configuredthis workarround ? . Do you think this 
could avoid the BGP session flaps?

Thanks in advance for your support




Best Regards

Isidoro



El 09/09/2011 18:58, Andrew Parnell escribió:
> We noticed this as well on a couple of our M7i running 9.x series
> code, but not on others running 10.x.  This is being caused by a
> particular prefix (212.118.142.0/24):
>
> rpd[5239]: xx.xx.253.192 (Internal AS xx) Received BAD update for
> family inet-unicast(1), prefix 212.118.142.0/24
>
> The easy solution is to simply filter out the offending prefix.  There
> are many ways this can be done, but the following did the trick for
> us:
>
> policy-options {
>      prefix-list bad-prefixes {
>          212.118.142.0/24;
>      }
>      policy-statement BGP-Import {
>          term block-bad-prefixes {
>              from {
>                  prefix-list bad-prefixes;
>              }
>              then reject;
>          }
> }
>
> Apply something like this to your BGP import and/or export policy as
> appropriate and you should be fine.
>
> Andrew
>
> On Fri, Sep 9, 2011 at 11:41 AM, Markus<universe at truemetal.org>  wrote:
>> All of a sudden without changing anything in the config I'm getting the
>> following on a M7i running 8.0R2.8:
>>
>> rpd[3019]: bgp_read_v4_update: NOTIFICATION sent to 89.146.xx.49 (External
>> AS xxxx): code 3 (Update Message Error) subcode 11 (AS path attribute
>> problem)
>>
>> The other end (Cisco) is getting:
>>
>> %BGP-3-NOTIFICATION: received from neighbor 89.146.xx.50 3/11 (invalid or
>> corrupt AS path) 0 bytes
>>
>> This is causing the BGP session to flap. It happens at arbitrary intervals,
>> sometimes once a minute, sometimes just once in an hour. CFEB and RE CPU are
>> at steady 100% when it happens.
>>
>> What can I do about this and what could be the cause? Help! :)
>>
>> Thanks!
>> Markus
>>
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