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Contributor
rnperki
Posts: 40
Registered: ‎04-14-2011
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Explanation of the resolve keyword in static route

Can anyone explain what the resolve keyword does in a static route statement?

 

I am looking at an example in the Junos Routing Essentials course and it does not explain it very well.

 

It says that Junos does not do recurssive lookups of next hops by default?

 

Can anyone clarify or point me to some documentation?

 

Thanks

 

Roger

 

I am a cisco guy and studying for my CCIE but this does not make sense

Recognized Expert
mhariry
Posts: 340
Registered: ‎06-01-2011

Re: Explanation of the resolve keyword in static route

Hi,

 

Not much links found

 

http://www.juniper.net/techpubs/en_US/junos10.0/information-products/topic-collections/config-guide-...

 

By default, static routes can point only to a directly connected next hop. You can configure an IPv4 route to a prefix that is not directly connected by resolving the route through the inet.0 and inet.3 routing tables. To configure an IPv4 static route to a prefix that is not a directly connected next hop, include the resolve statement:

 

- it means that you could configure any static route on direct connect IP only but if you want to make the next-hop of this static route on another router for example you couldn't by default and need resolve so the router will look on the routing table for this next-hop and if exist so the route will be valid and could forward traffic

 

Regards,

 

Mohamed Elhariry

 

JNCIE-M/T # 1059, CCNP & CCIP

 

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Mohamed Elhariry
2* JNCIE (SEC # 159, SP # 1059),JNCIP-ENT

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Trusted Contributor
acecanal
Posts: 149
Registered: ‎07-05-2011

Re: Explanation of the resolve keyword in static route

[ Edited ]

 

  Cisco automatically resolve recursive routes. Those which next hop is not under directly connected interface. But Junos dont behave this way, so you have to configure the resolve option.

 

   For example, cisco config using recursive routes :

 

      ip route 1.1.1.0 255.255.255.0 2.2.2.2

      ip route 2.2.2.0 255.255.255.0 3.3.3.3

 

      interface fastethernet 0/0

        ip add 3.3.3.1 255.255.255.0

 

    Usually the second static route is some dynamic learned route, this have no sense to configure two recursive statics.

 

    Under Junos this config will be something like this :

 

      set routing-options static route 1.1.1.0/24 next-hop 2.2.2.2 resolve

      set routing-options static route 2.2.2.0/24 next-hop 3.3.3.3

 

      set interface fe-0/0/0 unit 0 family inet address 3.3.3.1/24

 

        If you dont use the resolve option, the first static router will be hidden because this have no an active next hop.

 

 

Br
Alex

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