IPSEC/VTI Mesh with Cisco 7200 Series Routers

assuming gns3 c7200 dynamips appliances

IMAGE HERE

Initial setup

internal and mgmt interface

setup
    basic mgmt setup
    (passwords...)
    snmp? yes
    mgnt interface --> fa0/1
    fdx yes

    ! nethence
    192.168.1.254/24

    ! os3
    10.9.9.254/24

    ! nowhere
    10.99.99.254/24

front-facing/public interface

    conf terminal
interface fa0/0
    ! nethence
    ip address 123.0.0.1 255.255.255.0

    ! os3
    ip address 123.0.0.2 255.255.255.0

    ! nowhere
    ip address 123.0.0.3 255.255.255.0

    no shutdown
    exit

check

    ! os3-pc
set pcname os3-pc
ip 10.9.9.1/24 10.9.9.254
save
    ping 10.9.9.254

    ! nowhere-pc
set pcname nowhere-pc
ip 10.99.99.1/24 10.99.99.254
save
    ping 10.99.99.254

    ! nethence-pc
    ping 192.168.1.254
route add -net 10.9.9.0/24 gw 192.168.1.254
route add -net 10.99.99.0/24 gw 192.168.1.254

    ! nethence
    ping 123.0.0.2
    ping 123.0.0.3

    ! os3
    ping 123.0.0.3

    write memory

IPSEC/VTI tunnel 0

between nethence and os3

crypto isakmp policy 1
    encryption aes
    authentication pre-share
    group 2

point to the neighbor

! nethence
crypto isakmp key beep-beep address 123.0.0.2

! os3
crypto isakmp key beep-beep address 123.0.0.1

crypto ipsec transform-set some-transport-set esp-aes esp-sha-hmac 
    mode tunnel

crypto ipsec profile some-ipsec-profile
    set transform-set some-transport-set

define the tunnel interface

interface tunnel 0
    ! nethence
    ip address 10.199.199.1 255.255.255.0
    tunnel source 123.0.0.1
    tunnel destination 123.0.0.2

    ! os3
    ip address 10.199.199.2 255.255.255.0
    tunnel source 123.0.0.2
    tunnel destination 123.0.0.1

    tunnel mode ipsec ipv4
    tunnel protection ipsec profile some-ipsec-profile

you should see this appearing in the console

%LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0, changed state to up

static routes and enable routing

! nethence
ip route 10.9.9.0 255.255.255.0 tunnel 0
ip routing

! os3
ip route 192.168.1.0 255.255.255.0 tunnel 0
ip routing

check and save router configuration

! nethence-pc
ping 10.9.9.1

write memory

IPSEC/VTI tunnel 1

between nethence and nowhere

nethence

conf terminal
crypto isakmp key beep-beep1 address 123.0.0.3

interface tunnel 1
    ip address 10.209.209.1 255.255.255.0
    tunnel source 123.0.0.1
    tunnel destination 123.0.0.3
    tunnel mode ipsec ipv4
    tunnel protection ipsec profile some-ipsec-profile
    end

nowhere

conf terminal
    crypto isakmp policy 1
            encryption aes
            authentication pre-share
            group 2
            exit

crypto isakmp key beep-beep1 address 123.0.0.1

    crypto ipsec transform-set some-transport-set esp-aes esp-sha-hmac
            mode tunnel
            exit

crypto ipsec profile some-ipsec-profile
    set transform-set some-transport-set
    exit

interface tunnel 1
    ip address 10.209.209.3 255.255.255.0
    tunnel source 123.0.0.3
    tunnel destination 123.0.0.1
    tunnel mode ipsec ipv4
    tunnel protection ipsec profile some-ipsec-profile
    end

static routes and enable routing

! nethence
ip route 10.99.99.0 255.255.255.0 tunnel 1

! nowhere
ip route 192.168.1.0 255.255.255.0 tunnel 1
ip routing

check and save router configuration

! nethence-pc
ping 10.99.99.1

write memory

IPSEC/VTI tunnel 2

between os3 and nowhere

os3

conf terminal
crypto isakmp key beep-beep2 address 123.0.0.3

interface tunnel 2
    ip address 10.219.219.2 255.255.255.0
    tunnel source 123.0.0.2
    tunnel destination 123.0.0.3
            tunnel mode ipsec ipv4
            tunnel protection ipsec profile some-ipsec-profile
            end

nowhere

conf terminal
crypto isakmp key beep-beep2 address 123.0.0.2

interface tunnel 2
    ip address 10.219.219.3 255.255.255.0
    tunnel source 123.0.0.3
    tunnel destination 123.0.0.2
            tunnel mode ipsec ipv4
            tunnel protection ipsec profile some-ipsec-profile
            end

more static routes

! os3
ip route 10.99.99.0 255.255.255.0 tunnel 2

! nowhere
ip route 10.9.9.0 255.255.255.0 tunnel 2

check and save router configuration

! os3-pc
ping 10.99.99.1

write memory

TODO

Troubleshooting

%CRYPTO-6-IKMP_MODE_FAILURE: Processing of Informational mode failed with peer at 123.0.0.1

Tunnel0 is up, line protocol is down 

==> double check neighbor address and that sets/tags do match

Resources

Cisco IPsec VPN Hardware for Cisco 7200 Series Routers At-A-Glance https://www.cisco.com/c/dam/en/us/products/collateral/interfaces-modules/vpn-acceleration-module-2-plus/at_a_glance_c45-466108_v1.pdf

Chapter: Site-to-Site and Extranet VPN Business Scenarios https://www.cisco.com/c/en/us/td/docs/security/vpn_modules/6342/vpn_cg/6342site3.html

Cisco IPsec Easy VPN Configuration https://networklessons.com/uncategorized/cisco-ipsec-easy-vpn-configuration/

vpcs

How To Use VPCS in GNS3 https://protechgurus.com/how-to-use-vpcs-in-gns3/

vti

IPSec Static Virtual Tunnel Interface https://forum.networklessons.com/t/ipsec-static-virtual-tunnel-interface/2374/7

IPSec Static Virtual Tunnel Interface https://networklessons.com/cisco/ccie-routing-switching-written/ipsec-static-virtual-tunnel-interface/

Quick Configs - Dynamic VTI IPsec (virtual-template, unnumbered, keyring, isakmp) https://www.youtube.com/watch?v=c1FyP71dVOE

tuning

#100DaysOfLabbing - Day 1 & 2 https://showipintbri.blogspot.com/2018/07/100daysoflabbing-day-1-2.html

troubles

%CRYPTO-6-IKMP_MODE_FAILURE: Processing of Informational mode failed with p https://community.cisco.com/t5/other-security-subjects/crypto-6-ikmp-mode-failure-processing-of-informational-mode/td-p/90618

Cisco System Messages https://www.cisco.com/c/en/us/td/docs/ios/system/messages/guide/consol_smg.html

Chapter: Cisco System Messages Overview https://www.cisco.com/c/en/us/td/docs/ios/system/messages/guide/consol_smg/sm_cnovr.html


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