Questions tagged [gre]
Generic Routing Encapsulation is a tunnelling protocol, used to carry network layer protocols through encapsulation inside others.
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Difference between GRE over Ipsec and Ipsec over GRE
What I have learnt is that whenever protocol X is encapsulated inside another protocol Y, then we say protocol X over protocol Y. eg: we say video over http or text over http, that's because video/...
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How to implement VXLAN/GRETAP tunnel on Juniper MX routers?
Implementing VXLAN is widely documented for Juniper MX routers on connecting two networks. However, I find it's rather difficult to find a equivalent implement of the following Linux command:
ip link ...
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Inner header and Outer header in tunnel packet
What should be at Inner header and Outer header in tunnel packet ?
And then we have tunnel IP address(for both router), tunnel source IP address, tunnel destination IP address.
In my understanding, ...
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what is the purpose of GRE in UDP encapsulation if its unidirectional
I was going through this feature of GRE called GRE-in-UDP encapsulation. The RFC says it is unidirectional and the tunnel traffic is not expected to be returned back to the UDP source port values used ...
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BGP: Are Virtual Internet Exchanges more efficient than normal internet transit?
There are a number of virtual internet exchanges that BGP peer over VPN links when local presence is not available. Given the IP encapsulation overhead, and the fact that these routes still cross the ...
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IPSec over L2GRE scenario
I wanted to know if this is a valid scenario and if it is possible to implement.
There is a remote site A. and a Data center site B. Both A and B have a edge router which runs an IPSec tunnel. An ...
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Which technologies are most relevant for mobile broadband ISP bonding? [closed]
If I have edge router and core router (kind of Hub) and few ISP lines between them what are the most relevant technologies to be used for mobile broadband bonding?
Expected result is:
if one of ISP ...
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Multiple GRE tunnels towards single host using anycast IP
I'm trying to build the following network architecture:
Where clients try to connect to a backend server (e.g. SSH) by using a Public Anycast IP adddress (1.2.3.4), that routes the client to the ...
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GRE Source IP Spoofing
I've read this blog post, which said that "Unlike some other protocols, the source for GRE packets cannot be faked or spoofed." But why?
What is preventing me from setting an arbitrary ...
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GRE tunnel bridging and MTU mismatch
Background
My workplace has 2 office areas which is only 200 meters away from each other. They have their own local networks, their own Internet connections, with routers configured to fallback to the ...
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Why does IPsec not support Multicast/Broadcast?
Many sources site GRE as supporting broadcast/multicast and IPsec does not. Both GRE and IPsec are merely tunneling protocols. Therefore there is nothing inherent about tunneling protocols which ...
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Traffic sent to GRE Tunnel fails, but GRE Tunnel is up and OSPF adjacencies are formed
NEW INFO_7-12-21
R1#sho ipv6 rout 2001:db8:B2:200::2:2
Routing entry for 2001:db8:B2:200::2:2/128
Known via "static", distance 1, metric 0
Route count is 1/1, share count 0
Routing ...
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GRE, guarantee 1500 bytes MTU for end hosts
Is it possible to achieve 1500 byte MTU at the end host connections ignoring fragmentation overhead in this simple scenario using GRE.
I would like to configure R1 and R2 to do the fragmentation ...
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Why does GRE tunnel has lesser TxBS/RxBS than its physical interface?
Given for instance,
interface Tunnel200
tunnel destination 110.153.1.1
There's a static route for 110.153.1.1, pointing to physical interface Gi0/0.
Gi0/0 is only used for tunnel200.
Under show ...
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Router on one side of a GRE tunnel not adding OSPF route through the tunnel whilst the router on the other side is
I have configured GRE tunnel between the Dublin and Carlow routers with the following commands:
//Carlow
int tunnel 0
ip address 172.16.12.1 255.255.255.252
tunnel source s0/0/0
tunnel destination 87....
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