New here? Both routers are connected to the Internet. All of the devices used in this document started with a cleared (default) configuration. In this example, OSPF is used as the FortiOS supports multicast traffic directly inside IPsec.There is therefore no requirement to use GRE-IPsec to carry multicast traffic between two FortiGates. Let me show you a topology that we will use to demonstrate GRE: Above, we have three routers connected to each other. Each IP packet that comes from a workstation with destination the Internet will be wrapped into a GRE packet and diverted to the proxy box. I understood.Originally, nxos does not automatically check the tunnel status?In ios there is a keepalive setting. One question about this approach is if you use track and it detects that the remote end is not reachable what would happen? For mGRE tunnel interfaces, since there is no fixed tunnel destination, some of the previous checks for P2P tunnels are not applicable. Normally it would be impossible for the two IPv6 LANs to reach each other, but by using tunneling, the two routers will put IPv6 packets into IPv4 packets so that our IPv6 traffic can be routed on the Internet. may be individual addresses or /28 prefixes. The ability to mark an interface as down when the remote end of the link is not available is used in order to remove any routes (specifically static routes) in the routing table that use that interface as the outbound interface. Use this section to confirm that your configuration works properly. Tunnel source IP address on Router1 will be configured as the tunnel destination IP address on Router2. The following restrictions apply while configuring GRE tunnels: The router supports up to 500 GRE tunnels. This section describes the show
Thank you, very helpful! If the internet becomes unavailable, traffic is automatically redirected to the non-NATed tunnel on the transport interface. Up/up - This implies that the tunnel is fully functional and passes traffic. By All tunnel interfaces of participated routers must always be configured with an IP address that is not used anywhere else in the network. type=8, code=0, id=172, seq=1. After GRE tunneling, GRE packets must be protected by IPsec. If the Interface State Control feature is enabled for Dynamic Multipoint VPN (DMVPN) and none of the NHSs respond, then the line protocol is put in a down state. The show statistics tunnel command output now includes information from the hardware counters for each tunnel. the tunnel destination. Configuring a GRE tunnel involves creating a tunnel interface and defining the tunnel source and destination. Classic GRE tunnel is a point to point, Manual tunnel, Not scalable, Static IP on all endpoints. - OSPF is also used as a dynamic routing protocol (with multicast traffic, hence the need for GRE-IPsec with some vendors). One traffic flow, shown in green, remains within the overlay network and travels between the two routers in the usual fashion, on the secure IPsec tunnels that form the overlay network. id=20085 trace_id=9 func=print_pkt_detail line=4793 msg="vd-root, id=20085 trace_id=9 func=init_ip_session_common line=4944 msg=", id=20085 trace_id=9 func=iprope_dnat_check line=4659 msg="in-[port2], out-[]", id=20085 trace_id=9 func=iprope_dnat_check line=4672 msg="result: skb_flags-02000000, vid-0, ret-no-match, act-accept, flag-00000000", id=20085 trace_id=9 func=vf_ip_route_input_common line=2586 msg=", id=20085 trace_id=9 func=iprope_fwd_check line=636 msg="in-[port2], out-[toCisco], skb_flags-02000000, vid-0", id=20085 trace_id=9 func=__iprope_check line=2049 msg="gnum-100004, check-ffffffffa001e70e", id=20085 trace_id=9 func=__iprope_check_one_policy line=1823 msg="checked gnum-100004 policy-1, ret-matched, act-accept", id=20085 trace_id=9 func=__iprope_user_identity_check line=1648 msg="ret-matched", id=20085 trace_id=9 func=__iprope_check line=2049 msg="gnum-4e20, check-ffffffffa001e70e", id=20085 trace_id=9 func=__iprope_check_one_policy line=1823 msg="checked gnum-4e20 policy-6, ret-no-match, act-accept", id=20085 trace_id=9 func=__iprope_check line=2068 msg="gnum-4e20 check result: ret-no-match, act-accept, flag-00000000, flag2-00000000", id=20085 trace_id=9 func=__iprope_check_one_policy line=2020 msg="policy-1 is matched, act-accept", id=20085 trace_id=9 func=__iprope_check line=2068 msg="gnum-100004 check result: ret-matched, act-accept, flag-08010000, flag2-00004000", id=20085 trace_id=9 func=iprope_fwd_auth_check line=688 msg="after iprope_captive_check(): is_captive-0, ret-matched, act-accept, idx-1", id=20085 trace_id=9 func=fw_forward_handler line=697 msg=", id=20085 trace_id=9 func=ipsecdev_hard_start_xmit line=157 msg=", id=20085 trace_id=9 func=esp_output4 line=859 msg=", id=20085 trace_id=9 func=ipsec_output_finish line=498 msg=", id=20085 trace_id=10 func=print_pkt_detail line=4793 msg="vd-root, id=20085 trace_id=10 func=resolve_ip_tuple_fast line=4857 msg=", id=20085 trace_id=10 func=vf_ip_route_input_common line=2586 msg=". Go to solution JongSungPark94400 Beginner Options 03-23-2020 07:28 PM Hi Guys. The original IP packet carried inside the GRE packet: Generic Routing Encapsulation (IP) Flags and Version: 0x0000 Protocol Type: IP (0x0800), Internet Protocol Version 4, Src: 10.1.1.1, Dst: 10.2.2.2, 0100 . = Version: 4 . 0101 = Header Length: 20 bytes (5) Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT) Total Length: 84 Identification: 0x3bec (15340) Flags: 0x02 (Don't Fragment) Fragment offset: 0 Time to live: 63 Protocol: ICMP (1), Header checksum: 0xe8b7 [correct] Source: 10.1.1.1 Destination: 10.2.2.2Internet Control Message Protocol Type: 8 (Echo (ping) request) Code: 0 Checksum: 0xbb92 [correct] Identifier (BE): 174 (0x00ae) Identifier (LE): 44544 (0xae00) Sequence number (BE): 1 (0x0001) Sequence number (LE): 256 (0x0100) Data (48 bytes). New here? GRE encapsulates a payload, that is, an inner packet that needs to be delivered to a destination For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. GRE traffic (protocol 47) sent and received by the FortiGate: IPsec traffic (ESP) sent and received by the FortiGate: Verify the debug flow when PC1 attempts to ping PC2. There are no specific requirements for this document. The main drawback of GRE protocol is the lack of built-in security. The question was brought to me as to how to actually show the GRE tunnel itself. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. The following restrictions apply while configuring GRE tunnels: The router supports up to 500 GRE tunnels. by the tunnel source and tunnel destination address. Stephen_G. GRE enables the usage of protocols that are not normally supported by a network, because the packets are wrapped within other packets that do use . The
This may occur under conditions of a staticroute for the public interface being configured with an Administrative distance AD of 1 (the default), while the AD value on the static route for the IPsec tunnel interface (installed by the configuration of ip address overlapping where the IPsec tunnel interface) gets assigned an ip address on the same subnet as the public interface: In this scenario, the solution is to change the AD distance on the route for the public interface to match the same value on the route for the IPsec tunnel. 1. I've seen some use of ip sla between both tunnel ips. Follow the steps below to configure the GRE tunnel on both routers: CLI: Access the Command Line Interface on ER-L using SSH. A valid tunnel destination is one which is routable. I created a site to site VPN using the GRE tunnel on the RV340 Router.I want to pass a vlan tag over a VPN.Can vlan tag be delivered to Device with the following configuration?SiteA-> (with vlan tag) WAN-> VPN ------------ SiteB VPN-> LAN-> Device (with vlan tag). Enable NAT in the transport VPN (VPN 0) on the WAN-transportfacing interface, which here is ge0/0. Tunneling is a concept where we put packets into packets so they can be transported over certain networks. You will see that the NAT filter is built for Internet Control Message Protocol (ICMP). GRE (Generic Routing Encapsulation) is a simple tunneling technique that can do this for us. The number of keepalive packets received on the tunnel since it was last cleared by the administrator. Cross-check that the default-route from the service-side points to the Transport interface with NAT on. Also, verify that the endpoint IP address is not the same as the Transport interface. Learn more about how Cisco is using Inclusive Language. Possible values are: The number of packets received on the tunnel since it was last cleared by the administrator. This Deny Internet policy ensures that packets destined to the remote LAN never match the Internet Access policy. The tunnel endpoints send payloads through GRE tunnels by routing encapsulated Here is an example that can be used in order to verify that packets go out to the Internet.
The number of keepalive packets sent on the tunnel since it was last cleared by the administrator. shows how to configure a GRE tunnel between Router1 and Router2. Sending 5, 100-byte ICMP Echos to 172.30.2.2, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms, 2007 Cisco Systems, Inc. The number of packets sent on the tunnel since it was last cleared by the administrator. You will see that the NAT filter is built for, ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------. This data is stored as statistics in logical tables that are based on statistics - OSPF is also used as a dynamic routing protocol (with multicast traffic, hence the need for GRE-IPsec with some vendors). The tunnel mode. Decapsulation statistics also help you to detect the type of traffic as well. Specifically, if the line protocol for an interface is changed to down, then any static routes that point out that interface are removed from the routing table. Sending 5, 100-byte ICMP Echos to 20.1.1.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 16/33/60 ms. Sending 5, 100-byte ICMP Echos to 30.1.1.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 16/38/68 ms. Sending 5, 100-byte ICMP Echos to 40.1.1.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 16/23/36 ms, R1(config-if)#ip address 192.168.1.1 255.255.255.0, R3(config-if)#ip address 192.168.1.2 255.255.255.0, R3(config-router)#no auto-summary cy. Secured Connectivity 4-173, Then ping a host on the remote subnet as follows: router1# ping 10.0.6.2. The big advantage of GRE protocol is that it encapsulates L3 and higher protocols inside the GRE tunnel so routing updates and other multicast traffic can be successfully transferred over the tunnel. for Load Balancing feature, enables line rate GRE encapsulation traffic and enables flow entropy. Before you configure you must adjust (MTU) maximum transfer unit and MSS maximum segment size. Check the key exchange by using the show crypto isakmp policy command on the routers in question. The different statistics types include L2 Interface TX Stats, L3 Interface TX Stats, TRAP stats, On the right side, there is a Branch router that is supposed to be a branch office. GRE (Generic Routing Encapsulation) is a simple tunneling technique that can do this for us. Edited on configure. I am glad that my suggestion was helpful. nly IPsec in tunnel-mode is supported (no support for IPsec in transport-mode). In Releases 17.2.2 and later, on Network Address Translation (NAT) enabled transport interfaces are used for local internet exit. To display GRE tunneling Information, use the following commands: show ip interface show ip route show ip interface tunnel show ip tunnel traffic show interface tunnel show statistics tunnel The following shows an example output of the show ip interface command, which includes information about GRE tunnels. In order to make this interface up/up, a valid tunnel source and tunnel destination must be configured: So far, the tunnel has been configured as a point-to-point (P2P) GRE tunnel, which is the default. The GRE tunnel behave as virtual point-to-point link that have two endpoints identified An arbitrary forward-policy (e.g., from and to the IPsec interface itself) is therefore used to 'activate' IPsec:). Keepalives on the GRE tunnel interface are used in order to solve this issue in the same way keepalives are used on physical interfaces. In this example, a misconfigured ipc zone default configuration causes redundancy to be in the NEGOTIATION state and keeps such tunnel interfaces in a down state: In addition to the reasons previously outlined, the tunnel line state evaluation for the tunnel down reason can be seen with the show tunnel interface tunnel x hidden command as shown here: Note: There is an open enhancement to make the tunnel down reason more explicit in order to indicate that it is due to the redundancy state because it is notactive. Encapsulation statistics can help you to infer the source of the traffic, and decapsulation statistics provide However, there is no keepalive option in N9K. 2-pass to Single-pass migration, which means converting the same GRE tunnel, is not possible in a single configuration step. It is both administratively up and its protocol is up as well. You can look at the attributes for a tunnel with the show interface command. Administratively down/down - This implies that the interface has been administratively shut down. View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices, The tunnel source interface is in a down state, DMVPN Tunnel Health Monitoring and Recovery Configuration Guide, RFC 1701, Generic Router Encapsulation (GRE), RFC 2890, Key and Sequence Number Extensions to GRE, Generic Routing Encapsulation (GRE) Tunnel Keepalive, Technical Support & Documentation - Cisco Systems. configure default and static routing. Technical Tip: Configuring and verifying a GRE ove Support for GRE tunneling and GRE over IPsec in tunnel-mode is available as of FortiOS 3.0. Use these resources to familiarize yourself with the community: Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic. The information in this document was created from the devices in a specific lab environment. Indicates whether or not PMTUD is enabled. The range is from 10 - 30. ]. If your network is live, ensure that you understand the potential impact of any command. Upon reaching the tunnel endpoint, GRE In this post, we will see how to monitor your Cisco CSR VPN tunnel and BGP (Border Gateway Protocol) peer status using CloudWatch agent and continuously monitor metrics and logs to detect, correlate anomalies to track down the issues and can reduce troubleshooting time. How to check status the NXOS's GRE Tunnel ? This article describes how to configure and troubleshoot a GRE over an IPsec tunnel between a FortiGate and a Cisco router. Created on RFC 2784 supports GRE tunnel ports. How to detect IPsec GRE tunnel status? [
IOS routers have had the feature of GRE keep alive for quite a while. Example ICMP echo-request from PC1 to PC2: id=20085 trace_id=9 func=print_pkt_detail line=4793 msg="vd-root received a packet(proto=1, 10.1.1.1:172->10.2.2.2:2048) from port2. A consequence of this is that,by default, the local tunnel endpoint router does not have the ability to bring the line protocol of the GRE Tunnel interface down if the remote end of the tunnel is unreachable. Reset/down - This is usually a transient state when the tunnel is reset by software. Syntax:
Its IP address is 192.23.100.0/24, and it uses the default OMP port number, 12346, for overlay network tunnels. another protocol by means of encapsulation. There are also live events, courses curated by job role, and more. With this change, the tunnel interface dynamically shuts down if the keepalives fail for a certain period of time. an anycast address. Let me show you a topology that we will use to demonstrate GRE: Above, we have three routers connected to each other. Indicates the pmtd aging timer configuration in minutes.The default is 10. Other IP routers along the way do not parse the payload (the inner packet); they Only the unicast GRE traffic between the GRE endpoints is exposed to IPsec. ]. Find answers to your questions by entering keywords or phrases in the Search bar above. Encapsulation and decapsulation data is collected periodically or on demand. Ill use EIGRP for this: Ill activate EIGRP on the tunnel and loopback interfaces. Single Pass GRE Encapsulation Allowing Line Rate Encapsulation feature, also known as Prefix-based GRE Tunnel Destination Up/Down - The tunnel is up and the line protocol is down. Excellent ! I configured the GRE tunnel with 2 N9K.However, there is no keepalive option in N9K.How do I check the tunnel status between each other in N9K?I've seen some use of ip sla between both tunnel ips. The GRE over IPsec configuration in this article is based on the independent configuration of GRE settings and IPsec settings. Ensure that theendpoint-ip or endpoint-dns-name is something on the Internet that can respond to HTTP requests. The previous tutorial shown GRE tunnel configuration between Cisco router and Linux Core. Integrated Routing and Bridging, Configuring Virtual [
3. (Thats the reason we used IPSec to add an encryption layer and secure the GRE tunnel with the help of IPSec we get army-level encryption). If the remote LAN subnet (10.2.2.0/24) is missing in the routing table (such as if OSPF adjacency is down), packets destined to 10.2.2.0/24 would match the default-route and the Internet Access policy. To display GRE tunneling Information, use the following commands: For field definitions, refer to the
The following shows an example output for tunnel ID 1. Learn more about how Cisco is using Inclusive Language. How do I check the tunnel status between each other in N9K? ---------------------------------------------------------------------------------------------------------------------------------------------, ------------------------------------------------------------------------------------------------------------------------------------------------------------------, ------------------------------------------------------------------------------------------------------------------------------. Packets from VPN 1 are sourced. configure point-to-point tunnels between router 1 to 3 and router 1 to router 4 R1 (config)#interface serial 4/0 R1 (config-if)#ip address 1.1.1.1 255.0.0.0 R1 (config-if)#no shutdown Method Status Protocol, FastEthernet0/0 10.1.1.1 YES manual up up, Serial4/0 1.1.1.1 YES manual up up, FastEthernet0/0 20.1.1.1 YES manual up up, Serial4/0 1.1.1.2 YES manual up up, Serial4/1 3.3.3.1 YES manual up up, Serial4/2 4.4.4.1 YES manual up up, FastEthernet0/0 30.1.1.1 YES manual up up, Serial4/1 3.3.3.2 YES manual up up, FastEthernet0/0 40.1.1.1 YES manual up up, Serial4/2 4.4.4.2 YES manual up up, R1(config)#ip route 0.0.0.0 0.0.0.0 serial 4/0, R2(config)#ip route 1.0.0.0 255.0.0.0 serial 4/0, R2(config)#ip route 10.0.0.0 255.0.0.0 serial 4/0, R2(config)#ip route 30.0.0.0 255.0.0.0 serial 4/1, R2(config)#ip route 3.0.0.0 255.0.0.0 serial 4/1, R2(config)#ip route 4.0.0.0 255.0.0.0 serial 4/2, R2(config)#ip route 40.0.0.0 255.0.0.0 serial 4/2, R3(config)#ip route 0.0.0.0 0.0.0.0 serial 4/1, R4(config)#ip route 0.0.0.0 0.0.0.0 serial 4/2. The documentation set for this product strives to use bias-free language. The
Cisco Network Convergence System 5500 Series, show tunnel ip ea database tunnel-ip 109 location, Advanced If you need to pass a tag you might look into using l2tpv3. In some cases, after creating the static route for the public interface, the IPsec tunnel goes down. tunnel-ID
You can also configure BGP or IS-IS as the routing protocol. When we create a GRE point-to-point tunnel without any encryption is extremely risky as sensitive data can easily be extracting from the tunnel and misused by others. If the internet becomes unavailable, traffic is automatically redirected to the non-NATed tunnel on the transport interface. Go to solution wjsenqkf2 Beginner Options 09-07-2020 05:28 AM Hello, everyone I configured the GRE tunnel with 2 N9K. If you use NAT in this way on a vEdge router, you can eliminate traffic "tromboning" and allow for efficient routes, that have shorter distances, between users at the local site and the network-based applications that they use. Another approach might be to run a dynamic routing protocol over the GRE tunnel (something like EIGRP or OSPF) that builds a neighbor relationship and checks to be sure that the neighbor is reachable. Packets sent: 49632 Packets received: 12234, # diag debug flow show function-name enable, # diag debug flow show iprope enable# diag debug flow filter proto 1. Verify if the tunnel mode GRE encapsulation and decapsulation are enabled. Direct traffic to existing locally via VPN 0. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Cisco ASA firewall will redirect intercepted HTTP and HTTPS traffic to proxy box using GRE tunnel. The policies for phase 1 (key exchange) and phase 2 (transformation of the data) have to be the same between the hub router(s) and spokes. To check if the tunnel interface is up or down, use the show ip interface brief command as follows: To verify tunnel interface configuration, use the show interfaces tunnel command as follows: router# show interfaces tunnel number [accounting], Displays the number of packets of each protocol type that have been sent through the interface. The default tunneling mode is GRE. Use this section in order to confirm that your configuration works properly. command displays the GRE tunnel configuration and the pmtd aging timer information. encapsulation is removed and the payload is forwarded to the packet's ultimate destination. When you enable NAT, it allows traffic exiting from a vEdge router to pass directly to the Internet rather than being backhauled to a co-location facility that provides NAT services for Internet access. All rights reserved. On the left side, we have the HQ router, our headquarters. Before you establish the GRE, note the example screenshot below that shows you the five IPs you'll be working with. Lets see if both routers can reach each other: There we gothey can ping each other without any issues! This allows for the installation of an alternate (floating) static route or for Policy Based Routing (PBR) in order to select an alternate next-hop or interface. And passing a tag over a routed link is not possible. On the FortiGate, verify the routing table (RIB). This means that each tunnel endpoint does not keep any information about the state or availability of the remote tunnel endpoint. We do not have much detail about your environment, and perhaps there is something there that could change our suggestion. Its IP address is 10.1.12.0/24. Look for 'NAT' route entry in the RIB. New here? Enter configuration mode. The
The HQ and Branch router each have a loopback interface representing the LAN. Helped me to understand well. Syntax:
2023, OReilly Media, Inc. All trademarks and registered trademarks appearing on oreilly.com are the property of their respective owners. - IPsec in transport mode is used since data packets are already tunneled in GRE. Some vendors do not support multicast traffic (such as with OSPF or streaming) directly inside an IPsec tunnel.The multicast traffic is therefore tunneled in GRE, which itself is protected by IPsec. type=0, code=0, id=172, seq=1. In Cisco IOS Software Releases 15.4(3)M/15.4(3)S and later, the GRE tunnel line protocol state can follow the IPsecSecurity Association (SA) state, so the line protocol can remain down until the IPsec session is fully established. Static route: default-route to Internet ISP. You can look at the attributes for a tunnel with the show interface command. Tracker Status should be 'UP' in show interface VPN 0. View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices.
The. Here is why: Next steps would be configuration for VRF-lite aware GRE tunnel with IPsec? FastIron Command Reference. endpoint-dns-name
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