R1#configure terminal. Note that the tunnel destination is the mapped (static NAT) IP address of router R1 (30.30.30.3). This is a diagram of the basic overlay network topology used in this example: Every spoke is assigned from a pool of addresses of /112, but receives a /128 address. interface GigabitEthernet0 How to Configure GRE Tunnel IP Source and Destination VRF Membership Follow these steps to configure GRE Tunnel IP Source and Destination VRF Membership: SUMMARY STEPS enable configure terminal interface tunnel number ip vrf forwarding vrf-name ip address ip-address subnet-mask tunnel source { ip-address | type number } security-level 100 Fill out the form and our experts will be in touch shortly to book your personal demo. Made sure R1 tunnel destination match with R5 tunnel source and vice versa. This is because from ASA version 8.3 and later, any access-list statement must reference a Real IP address and not a Mapped IP address. Pre-Bestpath POI. Thats it for the routers. ip address 192.168.1.1 255.255.255.0 You can choose tunnel interface between 0-2147483647 depends on your router capacity. tunnel destination 50.50.50.1 Classic GRE tunnel is a point to point, Manual tunnel, Not scalable, Static IP on all endpoints. We will create a GRE tunnel between the HQ and Branch router and ensure that the 172.16.1. Then, make sure to specify which interfaces on the router are internal and which are external. Find answers to your questions by entering keywords or phrases in the Search bar above. This is exactly what makes this scenario a little bit different from others. He is a self-published author of two books ("Cisco ASA Firewall Fundamentals" and "Cisco VPN Configuration Guide") which are available at Amazon and on this website as well. Also, we must configure an access list on the ASA (applied on the outside ASA interface) which must allow GRE traffic from 50.50.50.1 to 20.20.20.1. We previously wrote about how to set up a generic routing encapsulation (GRE) tunnel for Incapsula IP Protection on an Ubuntu AWS Client. 172.16.1.1 Now both networks (192.168.1./24 and 192.168.2./24) are able to freely communicate with each other over the GRE Tunnel. GRE encapsulates a payload, that is, an inner packet that should be delivered to a destination network inside an outer IP packet. At this point, you have a choice, to configure the new IP on the server itself, or use the network address translation (NAT). The VRF table defines the VPN membership of a customer site attached to the network access server (NAS). !Now configure GRE Tunnel Interface. ip tcp adjust-mss 1360 As shown, router R1 is behind a Cisco ASA firewall. It is a myth you have to adjust the MTU on the Tunnel interface. How to configuring GRE Tunnel instead of virtual link.? Router R1 has Public IP 101.1.1.1 and Router R2 has Public IP 102.1.1.1. I fixed it. Configurable tunnel source using interface. Find the right plan for you and your organization. If you've already registered, sign in. Although, you can configure the GRE Tunnel over the IPSec VPN for securing the GRE tunnel. It also supports encapsulating IPv4 broadcast and multicast traffic. tunnel source 20.20.20.1 From versions prior to 8.3, the opposite was true. I wish you have mentioned IPsec for the same scenario because I am not able to implement it. Generic Routing Encapsulation (GRE) provides a simple approach to transporting packets of one protocol over another protocol using encapsulation. Instead of, we can create a site to site VPN tunnel as you mentioned in the discussion between R2 and ASA and allow the traffic only between the two loopback interfaces create on R1 and R2. Static routing sends traffic from the Incapsula Protected IP to a fixed address for your server. external bgp ( e bgp) operates in between the multiple autonomous systems bgp features bgp is an open standard protocol exterior gateway protocol designed for inter-as domain routing to scale huge. I know you have to adjust it for MPLS networks so I thought would be required here as well. HWnGW@W @1Xb>pth5 [" EdyhfElOL8x?=:Z!N+JQZ/QKx?=BL_Vuvq/WKc}-ZJ2hKSnobDBP>&xY*gDEWb",RmE}wbl.bd~\.%./pW\ubik1[3b|8ptqL_`)\W;UL|>MDAU(?&. Success rate is 100 percent (5/5), round-trip min/avg/max . Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. Along with the IP address, you also need to configure local and remote public IP addresses as well. ,\G3: (U19$7T.Jmzio?/C~;_!Dlo_+lq=@lPV:#+u.Y1 qH7cp+&vU [E|.3wg5=bb&Oo2]\Q_@4XLLWC [CLhF= {YD"i9( NL*[`eY Hr!w4 %RTDK&*|x=o@=%6`?.f{F6+p{ mT4/5II7;n3r$EO :6q 4#`O=Umb(36id|F/N+^di(Ov}h3Jo9d1Dom:`'dJ|aIR+h8]_=**;82|qqF Cisco Express Forwarding (CEF) switching is also now commonly used by the IPv6 and other tunneling protocols. 255.255.255. _f%t&j9)PJ31xS1OE$E:V MR*0ClJ-nL3h'Kz{,>f? 4 0 obj Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco that allows the encapsulation of a wide variety of network layer protocols inside point-to-point links.. A GRE tunnel is used when packets need to be sent from one network to another over the Internet or an insecure network. The first route is the default route pointing to the ISP and another one is the route for the GRE Peer end LAN subnet. Generic Routing Encapsulation (GRE) is a networktunnelingprotocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links or point-to-multipoint links over an Internet Protocol network. ! A GRE tunnel is used when IP packets need to be sent from one network to another, without being parsed or treated like IP packets by any intervening routers. The first step is to configure your firewall device with the appropriate tunnel interfaces. Basic interface configuration Then configure GRE Tunnel In the first two commands ("interface tunnel " and "ip address "), we enter interface tunnel mode and configure IP addresses of the GRE tunnel interfaces in the same subnet (12.12.12./30) so that we don't have to specific any routing protocol for routing between them. IPSec Transport mode is not used by default configuration and must be configured using the following command under the IPSec transform set: R1 (config)# crypto ipsec transform-set TS esp-3des esp-md5-hmac. This set up works with IPSEC over GRE? The APs are either autonomous or connected to a wireless LAN controller (WLC). For example, in Mobile IP, a mobile node registers with a Home Agent. Release 7.3.1. <>stream One platform that meets your industrys unique security needs. !Allow GRE traffic from R2 to R1. The ACL created above is for ASA version 8.3 and later. ll GRE Tunnel Configuration In Router 0, we will create the Tunnel interface and then give this interface an IP Address. Customers Also Viewed These Support Documents, Glimpse of "EIGRP name mode configuration", Understanding Wireless Client Authentication. This feature introduces the tunnel ttl disable command. GRE is initially defined in rfc1701. IS-IS. Use a Cisco device which works properly with Multicast. endobj So, lets configure the GRE Tunnel. 97y$`%'_k>=Rh6Vl_Di$vzq=%T4xpl("S{MI9X@j`BowDD1-23h*XK0zx3pt5\tdcMr=5.kFjBYxZtYa(Gv@KAa)GiS!QIWW]1; That completes your configuration. *8LoD55vc ez#N+_F #g*-*UH*8#];W>sqz",+P5Aeu->ANgW,~W%jQqOc)M]vlOB%bHsl You can verify it by pinging, Configure a static route on your router device (this will direct traffic toward it). Each tunnel interface is assigned an IP address within the same network as other Tunnel interfaces. 2 0 obj With this configuration, traffic directed to your network through the GRE interface must return through the same interface. Unfortunately Cisco ASA does not support GRE tunnel terminated on the device itself. A VRF table stores routing data for each VPN. These RGs or CPE can be configured in bridged mode, and Ethernet over Generic Routing Encapsulation (GRE) tunnels can be used to forward Ethernet traffic to the aggregation device. In this configuration tutorial I will show you how to configure a GRE tunnel between two Cisco IOS routers. If you want the route to be symmetric, as a final step, configure policy-based routing to ensure the symmetric flow. Use network address translation (NAT) to translate the Incapsula Protected IP to the current IP address of your server. speed auto Nice blog. Both routers are connected to "the Internet" using the ISP router. If you have any questions, please let leave me acomment. When we use GRE? However, this is fully supported on Cisco routers. Internet in a VPN. /24 and 172.16.3. You can also configure Dynamic Routing Protocols between GRE Peers. Now if you ping a host to LAN2 from LAN1 (and vica-versa) you should get ICMP replies. . Enter the following commands to create an access list that will match traffic from the Incapsula Protected IP to any destination. 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Terms of Use and However, why would you want to do that? % Otherwise, register and sign in. New here? 48wt :-}kVtI FSgRZ7+@gp`!My~ABSr-Q64$N`/w~o6arJe+S1/D3/YNo&;iKl = However, we need to initiate the traffic towards the remote networks to make the tunnel up and run. In order to configure the GRE tunnel, you must need connectivity between two remote routers through static Public IP address. R1 and R2 can communicate using their Public IP addresses. Edgar#srint tun1 Building configuration. Choose one of the following for the corresponding steps: 2. This should work. ip mtu 1400 Access the CLI of any of the router and initiate a ping to the GRE LAN Subnet. When configuring GRE, a virtual Layer3 " Tunnel Interface " must be created. ip address 30.30.30.2 255.255.255.0 So, just initiate the traffic towards the remote subnet. GRE Tunnel. I would suggest using GRE with IPSEC protection between the routers instead of terminating a different IPSEC tunnel on the ASA. Enter your Email below to Download our Free Cisco Commands Cheat Sheets for Routers, Switches and ASA Firewalls. Interface and Hardware Component Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 7.5.x Configuring GRE Tunnels Contents. You would have two different tunnels, one for GRE (just like the one we describe here) plus the IPSEC tunnel. In this example, Im taking 10.10.10.0/30 network. This module . It is important to allow the tunnel protocol through a firewall and to allow it to pass access control list (ACL) checking. Were including instructions for Cisco routers because they continue to be the most popular brand of enterprise routers and network switches. Generic Routing Encapsulation (GRE) is a network tunneling protocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links or point-to-multipoint links over an Internet Protocol network. This capability is now extended to the Cisco 8000 Series Routers. GRE allows routing of IP packets between private IPv4 networks which are segregated over public IPv4 Internet. EIGRP PE-CE with Backdoor Links. Resolution Configure ttl for GRE tunnel, set to 64: Put a static Arp entry onto your router/firewall. Even the latest generation of ASA 5500-X series with the latest version of 9.x does not support termination of GRE on an ASA interface. 3 0 obj Generic Routing Encapsulation (GRE) is a tunneling protocol that provides a simple generic approach to transport packets of one protocol over another protocol by means of encapsulation. access-list OUT-IN extended permit gre host 50.50.50.1 host 20.20.20.1 duplex auto In this article, we configured the GRE tunnel on Cisco Routers. Mobile nodes access the Internet over Wi-Fi access points (APs). [If] the DF bit is set, and the datagram size (1500 bytes) is greater than the GRE tunnel IP MTU (1476), the router will drop the datagram and send an ICMP fragmentation needed but DF bit set message to the source of the datagram. With GRE, a virtual tunnel is created between the two endpoints (Cisco routers) and packets . Guidelines and Limitations for Configuring GRE Tunneling 4 Configuring GRE Tunneling . Here is my new running config for R1 and R5: R1#show run. Enter your email address to subscribe to this blog and receive notifications of new posts by email. R1 (config-if)#ip mtu 1400. There are two ways to configure NAT translation: Full network address translation of the entire address, and port address translation (PAT) of specific ports. Home>Blog>Setting up a GRE Tunnel on a Cisco Router. Two scenarios that come to my mind now include passing routing protocols (such as OSPF) between two remote sites, and also passing multicast traffic through the GRE tunnel from one site to another. I have debug on outside router and when I ping from inside I can see that traffic arrives on outside routere. Autonomous System Override. Here, you can get Network and Network Security related Articles and Labs. i followed his video and try to configure the GRE tunneling on R1 and R3 however i managed to bring up the interface tunnel 0 up the interface but after i finish the ip address.