[j-nsp] Route Reflecting & Next-Hop Self

[Kevin Hodle]

Hi Dan,

Instead of 'from external' you need 'from route-type external', like so:

term external-nexthopself {
    from {
        protocol bgp;
        route-type external;
    }
    then {
        next-hop self;
        accept;
    }
}

HTH,
Kevin

On Fri, Sep 5, 2008 at 9:26 AM, Dan Armstrong <dan at beanfield.com> wrote:
>
> I was trying to make a generic policy statement that I could deploy across all our boxes... this is not possible if we name ebgp peers specifically, and if we change transit providers - we have to keep track of changing policy statements as well... kind of messy.
>
>
>
> Chuck Anderson wrote:
>>
>> On Thu, Sep 04, 2008 at 10:08:45PM -0400, Dan Armstrong wrote:
>>
>>>
>>> In IOS, if I set next-hop self in a neighbor relationship with an  RR-Client, it sets the next-hop to itself for routes learned from local  eBGP sessions, but leaves the next-hop unchanged for routes that it's  passing on from other fellow route-reflectors...
>>>
>>> The *problem* is that in JunOS, if I set next-hop self on a neighbor  relationship with an RR-Client, it sets the next-hop to itself all the  time, even on routes it's passing on from other fellow route-reflectors,  effectively sucking all traffic into the route reflector and totally  defeating the purpose of route reflecting.
>>>
>>
>> That's just the way it is in JunOS--not much policy-related behavior is hard-coded into JunOS like it might be in other vendors.  This gives you the most flexibility in writing policy to do exactly what you want.
>>
>>
>>>
>>> Now, of course we can policy-statement our way out of this - with big  messy kludgey stuff, but it seems to me that there has to be a fairly  simple and elegant way to do this, since it's pretty common, no?
>>>
>>> (My current kludge is to set an import policy on my eBGP sessions that  tag each route with a community called "HERE", have an export policy  towards all my iBGP neighbors to set next-hop self if the route is  tagged with the community "HERE", then strip it off - so that the  community "HERE" never leaves any box.)
>>>
>>
>> That is one recommended method.  The other is to match the eBGP neighbor and only apply next-hop self to routes from your eBGP peers.
>>
>> e.g. in your IBGP export policy (from the JNCIP study guide):
>>
>> term 3 {
>>    from {
>>        protocol bgp;
>>        neighbor [ 172.16.0.14 172.16.0.18 ];
>>    }
>>    then {
>>        next-hop self;
>>    }
>> }
>>
>> where 172.16.0.14 and 17.16.0.18 are eBGP peer addresses.
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>>
>
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