This form of encapsulation is often referred to as tunneling. I know that i can do a show crypto isakmp sa and it will show the ipsec. Generic routing encapsulation gre is a tunneling protocol developed by cisco systems that encapsulates a wide variety of network layer protocols inside virtual pointtopoint links over an internet protocol internetwork. Configuring pointtopoint gre vpn tunnels unprotected gre. Generic routing encapsulation gre page 5 configuration example figure 4. If your multicast over gre tunnel is not working, one of these can be the cause. Configuring gre tunnel through a cisco asa firewall in this configuration tutorial i will show you how to configure a gre tunnel between two cisco ios routers. Support is not available for the fol lowing features in ios xe 16. Cisco content hub layer 2 over multipoint gre l2omgre. In this configuration, mpls traffic that is destined to the other side of the nonmpls network is sent through a single gre tunnel.
Use the vpninterfacegre template for all vedge cloud and vedge router devices. Cisco asr 9000 series aggregation services router mpls layer 3 vpn configuration guide ol2848601. Pointtopoint gre over ipsec design guide ol902301 sizing the branch sites 510 tunnel aggregation and load distribution 511 network layout 511 appendix a scalability test bed configuration files a1 cisco 7200vxr headend configuration a1 cisco catalyst 6500sup2vpnsm headend configuration a2. Gre is primarily intended to allow devices running a given network layer protocol to communicate over.
Porwal configuring a gre tunnel involves creating a tunnel interface. Configuring generic routing encapsulationgre tunnel ip. Gre can encapsulate many kinds of network layer, data link layer, or multicast protocols into an ip packet. The gre tunnel is between the west and east routers in ospf area 0. Interface and hardware component configuration guide. You will also configure the ospf routing protocol inside the gre vpn tunnel. Generic routing encapsulation gre is one of the available tunneling mechanisms which uses ip as the transport protocol and can be used for carrying many different passenger protocols. Refer to important information on debug commands before you use debug commands. Ensure that the 00 route used for dr1 the gre tunnel has a lower cost than passthrough or any other service type. The implementation of this feature allows you to configure a tunnel source and destination to belong to any vrf.
A gre tunnel is established on a router level and differs depending on the hardware type or service you use. The question was brought to me as to how to actually show the gre tunnel itself. Gre tunneling feature guide catalyst 3850 switches. Virtual private networking vpn is often deployed to create private.
In this lab, you will configure an unencrypted pointtopoint gre vpn tunnel and verify that network traffic is using the tunnel. In this article, well take you through the steps to configure a gre tunnel on a cisco router. In this configuration, mpls traffic that is destined to the other side of the non mpls network is sent through a single gre tunnel. Gre uses the same protocol identifiers that ethernet. Topology of the advantech to advantech router configuration example. When a service, such as a firewall, is available on a device that supports only gre tunnels, you can configure a gre tunnel on the vedge router to connect to the remote device by configuring a logical gre interface. Zscaler integration by using gre tunnels and ipsec tunnels. Configuring a tunnel with generic routing encapsulation. I have 2 device cisco catalyst 3850 and cisco catalyst 4500 in vss mode i try to configure a gre tunnel from this device but the tunnel doesnt work. Ip address of the gre tunnel interface 0 tunnel source ethernet0. Gre is stateless and has no knowledge of the configuration or even existence of the remote tunnel endpoint. The l2omgre feature associates a vlan interface with an mgre tunnel interface. If i try to build the tunnel from the catalyst 3850 to cisco router 1841 with the same configuration all works fine.
Configuring device a tunnel destination ip address 2. Tunneling provides a mechanism to transport packets of one protocol within another protocol. Implementing generic routing encapsulation documents free. Here is an example of a tunnel set up between two cisco routers. The below example explain about how to create simple gre tunnels between endpoints and the necessary steps to create and verify the gre tunnel between the two networks. Support is avaliable for ipv4 multic ast over pointtopoint generic routing encapsulation gre tunnels. I know that i can show int tunnel0 and it will show me the status of the tunnel interface. The tunnels behave as virtual pointtopoint links that have two endpoints identified by the tunnel source and tunnel destination addresses at each endpoint. Similarly, the backup gre tunnel to zscaler must have a higher cost than that of the primary gre tunnel. The host or device at each end of the configured tunnel must support both ipv4 and ipv6 protocol stacks. Generic routing encapsulation gre configuration guide. Configuring gre tunnel through a cisco asa firewall. Headends are p2p gre and crypto tunnel aggregation routers servicing multiple p2p gre over ipsec tunnels for a prescribed number of branch office locations.
1092 79 1323 356 1176 662 45 570 421 623 1208 1376 614 1209 386 1346 1492 482 1139 1309 1410 176 350 732 1540 1203 1454 605 1116 680 1504 883 1065 1470 452 1262 329 1319 1463 148 760 827 196 237 1392 471 1405 947