Routing
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GRE without known dest. address

‎12-19-2018 07:56 AM

Hi Guys, 

 

Could you please help me in the following topic: 

Is that possible to configure a GRE tunnel without known tunnel destination IP (source and the range  which has to be used within the tunnel is known)  and establish a BGP session between the endpoint? If yes, could you please help me how? 

 

Thanks in advance, 

A

4 REPLIES 4
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Routing

Re: GRE without known dest. address

‎12-19-2018 09:55 AM

I think you are looking for dynamic gre tunnels and the bgp "allow" option. it can be done if you know the destination network subnet range like /24, /16 etc

 

R1:-
+++++++
set routing-options dynamic-tunnels DEMO source-address 172.27.0.26
set routing-options dynamic-tunnels DEMO gre
set routing-options dynamic-tunnels DEMO destination-networks 172.27.0.0/24

set routing-options autonomous-system 100
set protocols bgp group DEMO type internal
set protocols bgp group DEMO local-address 172.27.0.26
set protocols bgp group DEMO allow 172.27.0.0/24

 

R2:-
++++++
set routing-options autonomous-system 100
set protocols bgp group DEMO type internal
set protocols bgp group DEMO local-address 172.27.0.25
set protocols bgp group DEMO neighbor 172.27.0.26

set routing-options dynamic-tunnels DEMO source-address 172.27.0.25
set routing-options dynamic-tunnels DEMO gre
set routing-options dynamic-tunnels DEMO destination-networks 172.27.0.0/24

 

Please go through this post: https://forums.juniper.net/t5/Routing/Dymanic-GRE-Tunnel-VPN/td-p/92212

 

 

 

Thanks,
Nellikka
JNCIE x3 (SEC #321; SP #2839; ENT #790)
Please Mark My Solution Accepted if it Helped, Kudos are Appreciated too!!!
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Re: GRE without known dest. address

‎12-20-2018 06:12 AM

thanks for the answer.  That was all which was known/given: address inside the tunnel, which is a /30 network and our source. 

I am thinking now about the same solution which you provided and cannot think anything else. 

 

 

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Routing

Re: GRE without known dest. address

‎12-24-2018 03:57 AM

what could be wrong withy my config? 

 

Router4: 

 

set routing-options static route 1.1.1.1/32 next-hop 192.168.0.201

set routing-options router-id 4.4.4.4

set routing-options autonomous-system 65501

set routing-options dynamic-tunnels GRE source-address 4.4.4.4

set routing-options dynamic-tunnels GRE gre

set routing-options dynamic-tunnels GRE destination-networks 172.16.0.0/24

 

set protocols bgp group EX type internal

set protocols bgp group EX family inet-vpn unicast

set protocols bgp group EX export ALLBGP

set protocols bgp group EX neighbor 1.1.1.1 multihop

set protocols bgp group EX neighbor 1.1.1.1 local-address 4.4.4.4

set protocols bgp group EX neighbor 1.1.1.1 peer-as 65501

 

ROUTER1: 

set routing-options static route 4.4.4.4/32 next-hop 192.168.0.204

set routing-options router-id 1.1.1.1

set routing-options autonomous-system 65501

set routing-options dynamic-tunnels GRE source-address 1.1.1.1

set routing-options dynamic-tunnels GRE gre

set routing-options dynamic-tunnels GRE destination-networks 172.16.0.0/24

 

set protocols bgp group EX type internal

set protocols bgp group EX family inet-vpn unicast

set protocols bgp group EX export ALLBGP

set protocols bgp group EX neighbor 4.4.4.4 multihop

set protocols bgp group EX neighbor 4.4.4.4 local-address 1.1.1.1

set protocols bgp group EX neighbor 4.4.4.4 peer-as 65501

 

thanks in advance

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Routing

Re: GRE without known dest. address

‎01-12-2020 08:34 PM

Hi Nellika,

 

Thanks for the information. I think I got similar task on my previouos JNCIE lab exam. I need to configure GRE tunnel without known destination address. And at that time I never tried anything like that so I dont know what to configure or what is the name of the feature. 

Regards,

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