ipsec gre tunnel configuration cisco router pdf

show crypto isakmp sa Shows the phase 1 security associations by displaying the router's IKE SA. Since GRE is an encapsulating protocol, we adjust the maximum transfer unit (mtu) to 1400 bytes and maximum segment size (mss) to 1360 bytes. View with Adobe Reader on a variety of devices, IP Security Troubleshooting - Understanding and Using debug Commands, IP Security (IPSec) Technology Support Page. View with Adobe Reader on a variety of devices, PIX/ASA 7.x and later : VPN/IPsec with OSPF Configuration Example, Configuring IPsec Router-to-Router Hub and Spoke with Communication Between the Spokes, Configuring Router-to-Router IPSec (Pre-shared Keys) on GRE Tunnel with IOS Firewall and NAT, Adjusting IP MTU, TCP MSS, and PMTUD on Windows and Sun Systems, Troubleshooting the PIX to Pass Data Traffic on an Established IPSec Tunnel, Cisco Secure PIX Firewall Command References, Technical Support & Documentation - Cisco Systems. (13)T software and later should still work; however, Cisco highly recommends that you apply it just on the physical interface. Refer to Configuring Router-to-Router IPSec (Pre-shared Keys) on GRE Tunnel with IOS Firewall and NAT for information on how to configure the basic Cisco IOS Firewall configuration on a GRE tunnel with Network Address Translation (NAT). For example, access-list 101 permit gre host #.#.#.# host #.#.#.# (where the first host number is the IP address of the tunnel source of the GRE tunnel and the second host number is the IP address of the tunnel destination). 6 0 obj GRE usages IP protocol number 47. (J#9-*htZ3>4N#(d%3 ,Z X&;.LDRd,1Nu[g,hgY <> 2 0 obj This section provides information you can use to troubleshoot your configuration. For this purpose, we use IPSec to add an encryption layer and secure the GRE tunnel. endobj To test and verify this, all that is required is to ping the other end and force the VPN IPSec tunnel to come up and start encrypting/decrypting our data: Using the show crypto session command, we can quickly verify the encryption is in place and doing its work: Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms. >{3*zGb]>bCqz{M]g[^A*kr}l~4ba4W{8GXB#}YXSfarz # eMww`l5683"UG1Fv$,18uORzmgu_GA ;z={ Z4*3PTP;fA\70A*1ZZA6V$Q LOk;?Z(_ J?Du=c};+96R.Lai]g3ZGAdw?3dW@Z+._$J5;l#45i!1gg$XPn,i(:_wVI+/* :s4'Mm* Refer to Troubleshooting the PIX to Pass Data Traffic on an Established IPSec Tunnel for additional information on troubleshooting a PIX and IPsec tunnel. 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. Both tunnels must be configured at your gateway. endobj interface tunnel 0 ip address 192.168..1 255.255.255.252 tunnel source serial 0/0/0 tunnel destination 64.100.13.2 tunnel mode . Part Two - Configuring the GRE tunnel on the Cisco router Step 1 - Enter configuration mode. IPSec VPN tunnels can also be configured using GRE (Generic Routing Encapsulation) Tunnels with IPSec. It is important to note that packets travelling inside a GRE tunnel are not encrypted as GRE does not encrypt the tunnel but encapsulates it with a GRE header. GRE tunnels greatly simply the configuration and administration of VPN tunnels and are covered in our Configuring Point-to-Point GRE VPN Tunnels article. The information presented in this document was created from devices in a specific lab environment. flx +`fl9>HP2q"%bENOOOp:1r rI#eM]"XZj9 57;38H++v8uNK5j[5cMJe1? Now we need to create the transform set used to protect our data. show ipx route Displays the contents of the IPX routing table. 7ywmo3AH|muZ[j g'CmgHOLP;R$E`gbng+VpyOTO8f@6 )z*v>kpl[wg`e.V|}^ 7x}_T|P#??[8.YA N>=1=3N7f1D9,bW1aj,5Y"8B k%t\Wj,(dq\[]! The entire GRE payload will be encrypted using the same IPSec link. This configuration uses CLI commands. Learn more about how Cisco is using Inclusive Language. <> The IPX ping command is executed on router1 destined for router2. This example uses generic routing encapsulation (GRE) in order to accomplish routing between the different networks. This is the topology that we will use: Above we have 3 routers. <> 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. Here are some configuration considerations: With IOS 12.2(13)T software and later (higher numbered T-train software, 12.3 and later), the configured IPSec crypto map only needs to be applied to the physical interface and is no longer required to be applied on the GRE tunnel interface. We explain all the necessary steps to create and verify the GRE tunnel (unprotected and protected) and configure routing between the two networks. Use the physical interface (or the loopback interface) IP addresses to identify Internet Key Exchange (IKE) peers. But this is what I'm using and I cannot for the life of me figure out why it isn't building a security association. enTypSnPh*?znHS\*YLRT? The main drawback of GRE protocol is the lack of built-in security. GRE IPSec Transport Mode. A major difference is that GRE tunnels allow multicast packets to traverse the tunnel whereas IPSec VPN does not support multicast packets. refer to Cisco Technical Tips Conventions. I also checkedisakmp sa and an association wasnt built successfuly between R3 and R0 even though it was using the tunnel (very odd). YVj\F:%/=9w~f/ _xl>Wd* =}l"&tyzWeN!=eBs/e-MLIca zHl)4hQ)rmZI)y\_DNfI" c;%H%NlN^ $;#Yj,S++"X.%;S3e&T&E:'O~{''OKg^CcarxNlYtS*@sc,M7Q5INceo 9|b3sjpAyL6F LXT5,Sr{oo/{ WW:o,tnvXT=n76.jA7k*:unu ]$|iM7M:1B%PWO,&(juL First step is to configure an ISAKMP Phase 1 policy: The above commands define the following (in listed order): Next we are going to define a pre shared key for authentication with R1's peer, 2.2.2.10: The peers pre shared key is set to firewallcx. I HEa?3#& rEmmkPoG5k6>wAW v This section captures the debug command outputs on the routers configured with IPSec. % To configure Generic Routing Encapsulation (GRE) over an IPSec tunnel between two routers, perform these steps: Create a tunnel interface (the IP address of tunnel interface on both routers must be in the same subnet), and configure a tunnel source and tunnel destination under tunnel interface configuration, as shown: interface Tunnel0. O#fI2eQ'D{t"PLu>Fugc8 `N+3U I]N/ca%&C- Wqewb3%l``--J\'?^( %KZ~9Q6,[B1 ]ROlL>O/C!;Mb pHY+DV2 "@,$b)|J3O6qVmiiYg| SfAA2A~4(wP!]F@|gol, ( 9 0 obj If data protection is required, IPSec must be configured to provide data confidentiality this is when a GRE tunnel is transformed into a secure VPN GRE tunnel. NFrt<2tdc% pQ%'zwho_z]+h%NUZb~y;t`8AWE L5tP'z` 3'lX{h} qcW._BU dfe{7z2+(0qNv/3\=ryeB]jlz{su@e46,!oXL+b"$aY\}^2j*sVbh0LnBia 5T`5up 54M*SrlgAhUZjM0A1/?~|L;.oBZe This effectively exposes the GRE IP Header as it is not encrypted the same way it is in Tunnel mode. 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. I must have had a misconfigured netmask and crytpo map missplaced. This document uses the network setup shown in the diagram below. An icmp echo from one end will confirm this: Again, this result means that the two tunnel endpoints can see each other. endobj You can view the bug details for this issue at CSCdm10376 (registered customers only) . The diagram below shows the encapsulation procedure of a simple - unprotected GRE packet as it traversers the router and enters the tunnel interface: While many might think a GRE IPSec tunnel between two routers is similar to a site to site IPSec VPN (crypto), it is not. I'm trying to build a GRE Tunnel with IPSec encryption (I may be phrasing this incorrectly, I realize). <]/Interpolate true/Width 575/BitsPerComponent 8/Length 21495/Height 171/Filter/FlateDecode>>stream These steps are: IKE exists only to establish SAs (Security Association) for IPsec. The information in this document is based on these software and hardware versions: Cisco 3600 that runs Cisco IOS Software Release 12.4(8), Cisco 2600 that runs Cisco IOS Software Release 12.4(8), PIX Firewall (Lion) Software Release 6.3(5), PIX Firewall (Tiger) Software Release 6.3(5). %]o(%R~ns}=>>o#W}G>qG~@}o9=sNQPEY#::C D[X\C!t#RrU[GsU45/)G R [b1S1bHDwG w@Jm;X'Lrj5hV2d(#0q0gfE2>V8?vB Learn more about how Cisco is using Inclusive Language. This key will be used for allISAKMP negotiations with peer 2.2.2.10 (R2). %PDF-1.2 These are RFC 1918 addresses which have been used in a lab environment. 10 0 obj Note:Refer to Important Information on Debug Commands before you use debug commands. In this section, you are presented with the information to configure the features described in this document. Closing, we define the Tunnel source, which is R1s public IP address, and destination R2s public IP address. endobj &0 gt>iC7y()\&'( X_\c/gpZ[1-A}]bNv fK+8X?ul@uS()} 93 z;S^_- "MCSnU9fmC; Define local GRE tunnel interface and assign it an IP address by typing the following commands: SFN_Router(config)# interface tunnel 0 SFN_Router(config-if)# ip address 196.100.101.1 255.255.255. '2I?hGQcYZE 7e6?O _nbWOwwRYQg]v8& ,4|oX=h^ Ct[0l%HnF endobj Ide appreciate any help on understanding whats happening and why. IPSec can be used to encrypt GRE tunnels to provide network layer security for non-IP traffic, such as Novell Internetwork Packet Exchange (IPX), AppleTalk, and so forth. 3 0 obj FoEsgUj4_6B*w=w|r|!`MIT*Cr*RTT.yp^(NRiG,6m%Z`T3)uzvG^`UA5{Wy0=CmH,Q'v{M All of the devices used in this document started with a cleared (default) configuration. Before it can do this, IKE must negotiate an SA (an ISAKMP SA) relationship with the peer. R0:access-list 101 permit ip 10.0.0.0 0.255.255.255 172.16.0.00.0.3.255crypto isakmp policy 10encryption aes 256authentication pre-sharegroup 5crypto isakmp key vpn-key address 64.102.46.2crypto isakmp key vpn-key address 64.100.13.2crypto ipsec transform-set R0_SET esp-aes esp-sha-hmaccrypto map R0_MAP 101 ipsec-isakmpset peer 64.102.46.2set peer 64.100.13.2set transform-set R0_SETmatch address 101interface serial 0/0/0crypto map R0_MAP, interface tunnel 0ip address 192.168.0.1 255.255.255.252tunnel source serial 0/0/0tunnel destination 64.100.13.2tunnel mode gre ip, interface tunnel 1ip address 192.168.0.5 255.255.255.252tunnel source serial 0/0/0tunnel destination 64.102.46.2tunnel mode gre ip, ip route 172.16.0.0 255.255.252.0 192.168.0.2ip route 172.16.4.0 255.255.252.0 192.168.0.6, R3:access-list 101 permit ip 172.16.4.0 0.0.3.255 10.0.0.0 0.255.255.255crypto isakmp policy 10encryption aes 256authentication pre-sharegroup 5crypto isakmp key vpn-key address 209.165.118.1crypto ipsec transform-set R4-SET esp-aes esp-sha-hmaccrypto map R4_MAP 101 ipsec-isakmpset peer 209.165.118.1set transform-set R4-SETmatch address 101interface serial 0/0/0crypto map R4_MAP, interface tunnel 1ip address 192.168.0.6 255.255.255.252tunnel source serial 0/0/0tunnel destination 209.165.118.1tunnel mode gre ip, R4:access-list 101 permit ip 172.16.0.0 0.0.3.255 10.0.0.0 0.255.255.255crypto isakmp policy 10encryption aes 256authentication pre-sharegroup 5crypto isakmp key vpn-key address 209.165.118.1crypto ipsec transform-set R3-SET esp-aes esp-sha-hmaccrypto map R3_MAP 101 ipsec-isakmpset peer 209.165.118.1set transform-set R3-SETmatch address 101interface serial 0/0/0crypto map R3_MAP, interface tunnel 0ip address 192.168.0.2 255.255.255.252tunnel source serial 0/0/0tunnel destination 209.165.118.1tunnel mode gre ip. crypto ipsec transform-set R0_SET esp-aes esp-sha-hmac crypto map R0_MAP 101 ipsec-isakmp set peer 64.102.46.2 set peer 64.100.13.2 set transform-set R0_SET match address 101 interface serial 0/0/0 crypto map R0_MAP . Refer to Cisco Technical Tips Conventions for more information on document conventions. To configure Generic Routing Encapsulation (GRE) over an IPSec tunnel between two routers, you can refer to these steps as follows: 1. In software versions prior to this release, IPSec crypto maps need to be applied to both the tunnel interface and the physical interface. Refer to Adjusting IP MTU, TCP MSS, and PMTUD on Windows and Sun Systems for information about possible Maximum Transmission Unit (MTU) issues. Our example below covers GRE IPSec Tunnel mode. Basically when you configure a tunnel, it's like you create a point-to-point connection between the two devices. show crypto engine connection activeShows each Phase 2 SA built and the amount of traffic sent. <> x`}'htM'j-lBwtjRzqVEv)`X%[Q{RilDZxh5Qkn HYW"iQX%(E ,J`QX%(E 0-z~Y$@`|Dw/67 0#x;CC EaQ(o FP(+axHXjDf&4rHPj/@dUQLKU,[7hP @bxB@vnErmg} l[P7#5Uz@HRf D 15E|BEK*hX$.v;w"OI4\"92G-/ ! This document explains how to configure an IPSec tunnel connection between the Mediant 1000 MSBG and a Cisco router. The documentation set for this product strives to use bias-free language. 2022 Cisco and/or its affiliates. For explanation on the command outputs, refer to the IP Security Troubleshooting - Understanding and Using debug Commands document. isakmp sa and an association wasnt built successfuly, Customers Also Viewed These Support Documents. IPsec encrypts the two packets, adding 52 byes (IPsec tunnel-mode) of encapsulation overhead to each, in order to give a 1552-byte and a 120-byte packet. show crypto engine connections active Displays a list of active SAs with their associated interfaces, transforms and counters. The same configuration must be repeated for R2: Now both networks are able to freely communicate with each over the GRE Tunnel. A!dlD6&r!x]3M Note:Before issuing debug commands, please see Important Information on Debug Commands. from the MSBG to a loopback address on the Cisco router. Let me show you a topology that we will use to demonstrate GRE: Above we have 3 routers connected to each other. 10.31.4.52 a 10.31.4 . @p18p6\c1g `>4|SWnFNcc]Kw72#]Kyb >#'&Qm368i.\W1%6_$KC7P5,Sr Hence, the tunnel does not have any IP address configured. This results in two GRE + IPsec packets of 1500 (1476 + 24 = 1500) and 68 (44 + 24) bytes each. jLky ,}Q#-gyiH0ls 'J&V^dE)2M)/3F&\(b&rfQmuucR=nb~n~s(T4TC8V0r 1&1McB6H1t/G;LBG3ZN8t4-'WL_^>|r O|T_o=_Gyo~gk^`(:? So, let's configure the GRE Tunnel. This document illustrates an IP Security (IPSec) configuration using a generic routing encapsulation (GRE) tunnel between two routers. The GRE tunnel in this example is purely used for transporting non-IP traffic. The information in this document is based on the software and hardware versions below. By default, GRE does not perform any kind of encryption. endobj Ive attached the lab if someone wants to give it a try and help me solve this. Before attempting this configuration, please ensure that you meet the following prerequisites: knowledge of IPX configuration and routing, knowledge and configuration of GRE tunnels, working knowledge and configuration of IPSec. Create a tunnel interface (the IP address of tunnel interface on both routers must be in the same subnet), and configure a tunnel source and tunnel destination under tunnel interface configuration, as shown: 64.100.13.2 209.165.118.1 QM_IDLE 1026 0 ACTIVE, 209.165.118.1 64.100.13.2 QM_IDLE 1062 0 ACTIVE, 209.165.118.1 64.102.46.2 QM_IDLE 1073 0 ACTIVE. The HQ and Branch router each have a loopback interface that will represent their LAN connection. 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. $MOw{h_sK600pldc/|*B;vt2r ._ This document uses the configurations shown below. endobj Because most transport MTUs are 1500 bytes and we have an added overhead because of GRE, we must reduce the MTU to account for the extra overhead. GRE tunnel uses a tunnel interface a logical interface configured on the router with an IP address where packets are encapsulated and decapsulated as they enter or exit the GRE tunnel. Configure In this section, you are presented with the information to configure the features described in this document. Note:To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) . Again the "show crypto ipsec sa" would confirm the traffic selectors, provide the output for further review. GRE (Generic Routing Encapsulation) is a simple tunneling technique that can do this for us. The second tunnel acts as a backup tunnel. It could also potentially be that because your crypto ACL permits "ip" from the local networks, traffic is being encrypted over the crypto map without being sent over the tunnel interface. Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output. endobj 42bE7u-k`)) YeSFK Note:The IP addressing schemes used in this configuration are not legally routable on the Internet. endobj The previous tutorial shown GRE tunnel configuration between Cisco router and Linux Core. Written by Administrator. show crypto map Displays the crypto maps configured on the router along with its details such as crypto access lists, transform sets, peers etc. IPSec Transport mode is not used by default configuration and must . V:{z1@Kgdb @MfUc[QUUt_4L:/ Im trying to configure this lab and PC1 can ping Server, but for PC0 to ping server I had to configure a static route (, ip route 10.0.0.0 255.0.0.0 192.168.0.5), but not on PC1 (All routers have EIGRP configured.). The key parameters in the output are indicated in bold. ujIURI;o\'x=kT/^HhoKpB8xZHAn60;756p|9Ek6Y\lUdY%T2nl+zS!V\v346/^&MT{ku6vQ\=51-5SNMJSe4@0q*:cHBdN*k#C/Ig($ q#I*! The state displayed should be QM_IDLE for an IKE SA to be considered up and functioning. <> refer to Cisco Technical Tips Conventions. IPSec can be used to encrypt GRE tunnels to provide network layer security for non-IP traffic, such as Novell Internetwork Packet Exchange (IPX), AppleTalk, and so forth. In order to configure the GRE tunnel, you must need connectivity between two remote routers through static Public IP address. GRE IPSec modes are covered extensively in our GRE and IPSec GRE Over IPSec - Selecting and Configuring Gre IPSec Tunnel or Transport Mode. Each Tunnel interface is assigned an IP address within the same network as the other Tunnel interfaces. \81hf&vtD@,_k fYk8||ckz4WknDjv Wm\Ku|N?h_O&#H}:lj2 4!Lk_` }I0WrRTmiWP With GRE, a virtual tunnel is created between the two endpoints (Cisco routers) and packets are sent through the GRE tunnel. In certain earlier versions of Cisco IOS release, fast switching on the tunnel interface has to be disabled for it to work, due to a bug. Ive checked configurations but I must be missing something. Coming back to your question, regarding GRE inside IPSec, you should use gre as the protocol in the access list; that right, you shud get points for that !! Refer to Configuring IPsec RoutertoRouter Hub and Spoke with Communication Between the Spokes for With GRE, a virtual tunnel is created between the two endpoints (Cisco routers) and packets . <> Note:Crypto does not support the Cisco 7600 Series Router. Having the crypto map on the physical and tunnel interface when using the 12.2. 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. )@\Opz3CL2k(&]pi~K% 8 0 obj y 2=z$YTCeFVEcgd*8c1 a %Y^5t4AjwA k3* Suc4juv`(vbx=lP=76U=l$ >$Y>s*{0Ez*V-2>g]el@u lPeWkF+=/p1;c_zb(^90PRsI_\ #$.e&r0He9eO*'@{@?>:|; ,8{YSBr.T4.>[O\u-;J8`b0*kmk=D'F q5!s[wSVt&2?,Hhjku6UV&>ylVhqX&%an_o?Q[5 dv]KIz6 show ip routeDisplays IP routing table entries. Tracing route to 10.0.0.2 over a maximum of 30 hops: Find answers to your questions by entering keywords or phrases in the Search bar above. Ch 4}NMbz}:-ud$i*15=O!q4|*' QT7fG*vP@uy7'MY3}C ^o2w*tmS^xO~~ rS erZXKhL~Po[lg5v811biLSh$&:$SOz:qiH*kv~.i%'=w%$i>VnXf8Qg_mIk{kL[ IUw\w(_'#=(k>ho#L `&efPQ;/|aMW;f\{`:n43V)T!0`D 4U4c$qn&WUGOw_=@ pnany]3]Qk>)D_l]UujdswC'xSAHQ+zgUgIJGed;bYW+PV/+GfHepQ$ 9rmMv|dv]~LK3`3GQ_F;(#C`pYxQpW-|XHAwm>b5{Tv&'Y>Zz!>UFj3AAnb:S aRN>PU-Y2GO5Nq_C6>Hg .dZ=n&0+6s-Cf=:4~cxCad=z03z7])bi4D$gy>;z?%>XYW{VwD/~v;d_-~{!HI >&}=N!Xqa)r75(efW_Wn0+2^Wfm^g> BlhH2z*#;haSA8|B;zSkxL:z xl1Dg,5[LdN|,wvbNkBg In our example, both Tunnel interfaces are part of the 172.16.0.0/24 network. Hence, the tunnel does not have any IP address configured. A GRE tunnel is used when packets need to be sent from one network to another over the Internet or an insecure network. 2022 Cisco and/or its affiliates. Workstations on either network will still not be able to reach the other side unless a static route is placed on each endpoint: On R1 we add a static route to the remote network 192.168.2.0/24 via 172.16.0.2 which is the other end of our GRE Tunnel. First step is to create our tunnel interface on R1: All Tunnel interfaces of participating routers must always be configured with an IP address that is not used anywhere else in the network. As mentioned earlier, GRE is an encapsulation protocol and does not perform any encryption. v^Gip~>['ytJ_7{@?/?58QBP@rhiBZOFD1J)9vU+SP(3&u. The documentation set for this product strives to use bias-free language. RoutertoRouter IPSec (RSA Keys) on GRE Tunnel with RIP Configuration Example Document ID: 29780 Contents Introduction Prerequisites Requirements Components Used Conventions . If your network is live, make sure that you understand the potential impact of any command. <> debug crypto engine Shows information about the crypto engine performing encryption and decryption process. I cant really understand why. All rights reserved. ( ~\%-O1&H89|R8G > =@} >tqCN.| 9|`-2(v!L>N2r"+KN%5CH hjHBAJD6H%wKj1wSL~9O?zp} wy 'K[{O _N!LQ.dq*"K\M0 a:l4Z#G!iZ`R*++9XZ&,Z:FIOhuQr~WboN7MjI`kcC9<63! ,8ynzRLRMaCL8vtJI5r.`,3l X#ox\4{Z9/}i17L \ @|#gakJez|YwPSw`>[4Y}LBZ,f[( There is currently no verification procedure available for this configuration. The information in this document was created from the devices in a specific lab environment. XK"?H2. zJaBmvkUSR'|+E>QfCx'O u^iu%-=[kDR0nr%7 Posted in Cisco Routers - Configuring Cisco Routers. The connection is encrypted with the industry- . The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Check "show crypto ipsec sa" on R0 and confirm there are active SAs to R4 and the counters encaps|decpas increase when PC1 pings the server. The outputs on Router2 are similar. R!UMA:N#p!0a+(G ,qIcT\t_=.fy wXh&''8dz+ ~8>j@ Step 2 - Specify the tunnel interface source. b979 Ih4J&9a4$''FOcfJc*%3NAQZ+Zg`4U%=B]m?e%(Z-k) |la~>/pP8-v/hV.Ad_hX>\ |AO!y^H#mW?19=V G:M `>j 7u]O~g4c]WddiMIb0KH)t;lN)z]\QsB5JF(z/Bp NOTE In the legacy configuration, the crypto map had the following commands: Set Transform-set: In the legacy configuration, this is done in the crypto ipsec profile. New here? <> West and East are using their own Loopback0 interface as the tunnel source, and the other's Loopback0 as the tunnel destination. ."S,`IVOeew,tCB`osg!Xw ;=. ]Nz1Z |hDTgvkC =@}KWws}+ts_7Y;j1B The above commands defines the following: Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms, IKE SA: local 1.1.1.10/500 remote 2.2.2.10/500, IPSEC FLOW: permit 47 host 1.1.1.10 host 2.2.2.10, OpManager - Network Monitoring & Management, GFI WebMonitor: Web Security & Monitoring, Cisco Routers - Configuring Cisco Routers, GRE and IPSec GRE Over IPSec - Selecting and Configuring Gre IPSec Tunnel or Transport Mode. `6]C` >F?Je49 Turn off fast switching on the tunnel interface. 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. Yf`lx- k[r With GRE IPSec transport mode, the GRE packet is encapsulated and encrypted inside the IPSec packet, however, the GRE IP Header is placed at the front. 4 0 obj Refer to Cisco Technical Tips Conventions for more information on document conventions. <> endobj to configure for a VPN/IPsec with Open Shortest Path First (OSPF) without a GRE tunnel on Cisco PIX Security Appliance Software Version 7.x or Cisco Adaptive Security Appliance (ASA). As with R1, R2 router will inform us that the Tunnel0 interface is up: At this point, both tunnel endpoints are ready and can see each other. This provides us with the necessary military-grade encryption and peace of mind. The tunnel protection ipsec profile command states that any traffic that traverses the tunnel should be encrypted with the IPSec profile called ABC. 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. To configure a basic GRE tunnel: RouterA(config)# interface Tunnel0 RouterA(config-if)# ip address 1.1.1.1 255.0.0.0 RouterA(config-if)# tunnel source s0/0 RouterA(config-if)# tunnel destination 77.1.1.1 RouterB(config)# interface Tunnel0 RouterB(config-if)# ip address 1.1.1.2 255.0.0.0 RouterB(config-if)# tunnel source s0/0 RouterB(config-if . <>stream In large networks where routing protocols such as OSPF, EIGRP are necessary, GRE tunnels are your best bet. 11 0 obj GRE encapsulates the IP fragments, which adds 24 bytes to each packet. ipsec tunnels - GRE tunnels - gre over ipsec Certifications All Certifications CCNA CyberOps Associate CyberOps Professional DevNet Associate DevNet Professional DevNet Expert CCNP Enterprise CCNP Security CCNP Data Center CCNP Collaboration CCNP Service Provider CCIE Enterprise Infrastructure CCIE Enterprise Wireless CCIE Data Center CCDE }H5IU~agRmLg|2!IGXsPHb79 w)D"5sT6;P:', bI0KV]MA0GDat*4Omcr\NCoeffF )R4 This article will explain how to create simple (unprotected) and secure (IPSec encrypted) GRE tunnels between endpoints. 5 0 obj Although, you can configure the GRE Tunnel over the IPSec VPN for securing the GRE tunnel. A setting of 1400 is a common practice and will ensure unnecessary packet fragmentation is kept to a minimum. The GRE tunnel in this example is purely used for transporting non-IP traffic. I don't have packet-tracer to check your full configuration, you say you've got EIGRP configured on all routers, is the traffic being routed unencrypted? Only a single tunnel is operational at any time. IPSec encryption involves two steps for each router. This section provides information you can use to troubleshoot your configuration. 7 0 obj ")oTa1k}sCqXVW,Jq)8DIpQ7fdcR(W0J*Lyi`@^}`S/f@'i(E5c)g~ >o+gzW}#te'w`sO~O>zD&b4lyak}3Rc+1A|F9NQ%v}Hg B\b GU> S>| S>lJd~O;BZha7r8t{8\3 k,CehH`)R\ Weve named this TS: Finally, we create an IPSec profile to connect the previously defined ISAKMP and IPSec configuration together. Configure In this section, you are presented with the information to configure the features described in this document. In this section, you are presented with the information used to configure the features described in this document. In this lesson I will show you how to configure an encrypted GRE tunnel with IPSEC. Creating a point-to-point GRE tunnel without any encryption is extremely risky as sensitive data can easily be extracted from the tunnel and viewed by others. Z) f4j0J#R8% )/sO}yA6lhtb/O?xzSO"$>.{2N; All of the devices used in this document started with a cleared (default) configuration. This section describes how to configure two IPSec VPN tunnels on Cisco 881 ISR running Cisco IOS 15.0. y}C_3E[|IPMqJ%Hy ##_04 ViEG]GO3_-U+"NOVa\05Y'S-Kt`%S>]IH}q(vZe#0VaIz-zt][:>#6pw#-t/kYB*FV#1|E)L`rw-=f$rP{U8u^XE}pZw*|*_Yv+vT^6k#;bjp}Mc9ml>{z[ULUDG9:q2 You may have to install the VPN module in order for this to work. show crypto isakmp saShows the Internet Security Association Management Protocol (ISAKMP) Security Association (SA) built between peers. Also remember that the ip address given as tunnel destination should be globally routeable. The crypto access control list (ACL) should have GRE as the permitted protocol. 1 0 obj RoutertoRouter IPSec (RSA Keys) on GRE Tunnel with RIP Configuration Example Document ID: 29780 Contents Introduction Prerequisites Requirements Components Used Conventions . Weve named our IPSec profile protect-gre: We are ready to apply the IPSec encryption to the Tunnel interface: Now it's time to apply the same configuration on R2: Finally, our tunnel has been encrypted with IPSec, providing us with the much needed security layer. debug crypto ipsec View the IPSec negotiations of phase 2. debug crypto isakmp View the IKE negotiations of phase 1. show crypto ipsec sa Shows the phase 2 security associations by displaying a detailed list of the router's active IPSec SAs. Normal IP Security (IPsec) configurations cannot transfer routing protocols, such as Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF), or non-IP traffic, such as Internetwork Packet Exchange (IPX) and AppleTalk. I now can ping from PC0. (because the ip packet is first encapsulated by GRE and then AH/ESP headers are added). Refer to Configuring IPsec Router-to-Router Hub and Spoke with Communication Between the Spokes for information on how to configure a hub and spoke IPsec design between three routers. Refer to PIX/ASA 7.x and later : VPN/IPsec with OSPF Configuration Example for more information on how to configure for a VPN/IPsec with Open Shortest Path First (OSPF) without a GRE tunnel on Cisco PIX Security Appliance Software Version 7.x or Cisco Adaptive Security Appliance (ASA). 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. This section captures the show command outputs on the device Router1 when the IPX ping command is executed on Router1 destined for Router2. Use the OIT to view an analysis of show command output. Note:Use the Command Lookup Tool (registered customers only) to find more information on the commands used in this document. Next, we must create the Tunnel 0 interface on R2: R2s Tunnel interface is configured with the appropriate tunnel source and destination IP address. Prerequisites Requirements Ensure that you meet these requirements before you attempt this configuration: Both routers are connected to "the Internet" using the ISP router. Ensure that you meet these requirements before you attempt this configuration: Make sure that the tunnel works before you apply the crypto maps. As soon as we complete R1s configuration, the router will confirm the creation of the tunnel and inform about its status: Since the Tunnel 0 interface is a logical interface it will remain up even if there is no GRE tunnel configured or connected at the other end. Computer B 21.251.251.121.31.2. Refer to Configuring Router-to-Router IPSec (Pre-shared Keys) on GRE Tunnel with IOS Firewall and NAT for information on how to configure the basic Cisco IOS Firewall configuration on a GRE tunnel with Network Address Translation (NAT). "iii*-]')wAET0C'U)v^n\ECGdt?KolD?Nd;4I $U7q&6]Pq-^b2V00NrdBv^59 qNJ{hTqP]H4!vD\&+p0:V3e7~7x7z >g:{?7^~oKqbi^,2pO*VU, ~p0yF2~[b052Nt34&HN bJ$QwKDB 3gp48X8,Zz4 6YrS^/!Q# show ipx interface Displays the status and parameters of the IPX interfaces configured on the device such as the IPX network and node address. Make sure that the GRE tunnel works before applying the crypto maps. !1^a@DM!C2) t^B`(dIC2JEd~Q"4BBPE/56ckT/@LKwjJxP,3l{RT[ce/qT=dBGYVF?)K-S:X $ z-+V,9.6H@tH)#`FE-%\TtP"fL1h4d(-PF}#7jp$ge\y&.k9z%JEp1d?3 Xvy07Ierbv'X&_~Nu0?b[oJF6E%+Z_4tE|KjVRwp6tqCsxkW} W=,O8bYf1Hu\0 'gWYtlOg} nF%7m:1C>{.mp_sJ=Vs&2u[w0~sC=tPBp~r]rs&|u-O46>v j?m(qcNn|'gSQ3Vxf3sU/. For this reason, plus the fact that GRE tunnels are much easier to configure, engineers prefer to use GRE rather than IPSec VPN. All rights reserved. mS' 34.w9 eHb4]lp$8X@a/rsgLhJLj3 ` endstream This section provides information you can use to confirm your configuration is working properly. This document illustrates how to route between different networks that use a routing protocol and non-IP traffic with IPsec. When R1 receives a packet for 192.168.2.0 network, it now knows the next hop is 172.16.0.2 and therefore will send it through the tunnel. 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