Aviatrix solution can take care of networking, security and network segmentation for workloads deployed in public clouds by deploying transit networking solution using Aviatrix transit and spoke gateways. It is a standard and stamp-out (copy/paste and repeat) design that is applicable to any public cloud (e.g AWS, GCP, Azure and OCI).
There are situation when there is a need to connect to 3rd party devices or services to exchange routes or to provide additional connectivity. These services and devices could be in the Public Cloud or On-Premise. In those situation the Aviatrix transit can also connect to those devices and services in secure and encrypted fashion (e.g using L3 IPSec).
Following topology demonstrate a scenario where a business is using Cisco CSR (could be any service or instance from any vendor that supports IPSec) in the Cloud to terminate LISP. By virtue of using LISP, the business is forced into a sub-optimal design where an additional hop is necessary.
For this setup we are assuming that you have already deployed Cisco CSR from AWS marketplace
- Created Transit VPC and Spoke VPC directly from Aviatrix Controller UI (no need to login to AWS console)
- Deployed AVX Transit GW and AVX Spoke GW in their respective VPCs using the Aviatrix Controller UI
- Follow the Aviatrix Transit Networking workflow to connect to external 3rd party device (e.g Cisco CSR)
- For external connectivity eBGP is the preferred option and this is what we are using here
- If you want to connect via static route to external device, it is also possible but then you have to enable “ActiveMesh” on Aviatrix Transit and Spoke Gateways first
- Attached Spoke-VPC to Transit-VPC
Build the IPSec Tunnel From Aviatrix Transit Gateway to Cisco CSR
Configure Aviatrix Controller as shown below
Notice we are using the default IPSec Algorithms. My recommendation is to start with the default and change after if needed
After you have done the setup as above, you will notice an entry in the Site2Cloud (S2C) section of AVX-Controller automatically (The screenshot shows tunnel UP which is not correct. The tunnel will be in the down state at this time)
Click on the Name above and download the IPSec config.
Aviatrix Site2Cloud configuration. This connection has a single IPsec tunnel between customer gateway and Aviatrix gateway in the cloud. Tunnel #1 1: Internet Key Exchange Configuration Configure the IKE SA as follows Version : 1 Authentication Method : Pre-Shared Key Pre-Shared Key : Aviatrix1! Encryption Algorithm : AES-256-CBC Authentication Algorithm : SHA-1 Lifetime : 28800 seconds Phase 1 Negotiation Mode : main Perfect Forward Secrecy : Diffie-Hellman Group 2 DPD threshold : 10 seconds DPD retry interval : 3 seconds DPD retry count : 3 2: IPSec Configuration Configure the IPSec SA as follows: Protocol : esp Authentication Algorithm : hmac-sha1 Encryption Algorithm : AES-256-CBC Authentication Algorithm : HMAC-SHA-1 Lifetime : 28800 seconds Mode : tunnel Perfect Forward Secrecy : Diffie-Hellman Group 2 IPSec ESP (Encapsulating Security Payload) inserts additional headers to transmit packets. These headers require additional space, which reduces the amount of space available to transmit application data.To limit the impact of this behavior, we recommend the following configuration on your Customer Gateway: TCP MSS Adjustment : 1387 bytes Clear Don't Fragment Bit : enabled Fragmentation : Before encryption 3: Tunnel Interface Configuration Your Customer Gateway must be configured with a tunnel interface that is associated with the IPSec tunnel. Traffic that should go through the tunnel should be specified by following your gateway's configuration guide, using the information below. Gateway IP addresses: Customer Gateway : 184.108.40.206 Aviatrix Gateway Public IP : 220.127.116.11 Aviatrix Gateway Private IP : 10.60.0.92 Subnets: Customer Network(s) : N/A for transit network Cloud Networks(s) : N/A for transit network Tunnel Inside IP addresses: Customer Gateway : 169.254.48.97/30 Aviatrix Gateway : 169.254.48.98/30 Configure your tunnel to fragment at the optimal size: Tunnel interface MTU : 1436 bytes 4. Border Gateway Protocol (BGP) Configuration: The Border Gateway Protocol (BGPv4) is used to exchange routes from the VPC to on-prem network. Each BGP router has an Autonomous System Number (ASN). BGP Configuration: BGP Mode : true Customer Gateway ASN : 65002 Aviatrix Gateway ASN : 65003 Configure BGP to receive routes from on-prem network. Aviatrix Transit gateway will announce prefixes to your on-prem gateway based upon the spokes you have attached. For vendor specific instructions, please go to the following URL: http://docs.aviatrix.com/#site2cloud
Cisco CSR Configuration
This is how the above template translates into a Cisco CSR Config. ip-10-60-0-89#sh run Building configuration... Current configuration : 7936 bytes ! ! Last configuration change at 16:30:21 UTC Fri Oct 4 2019 by ec2-user ! version 16.12 service timestamps debug datetime msec service timestamps log datetime msec service password-encryption ! platform qfp utilization monitor load 80 no platform punt-keepalive disable-kernel-core platform console virtual ! hostname ip-10-60-0-89 ! boot-start-marker boot-end-marker ! ! vrf definition GS rd 100:100 ! address-family ipv4 exit-address-family ! logging persistent size 1000000 filesize 8192 immediate ! no aaa new-model ! login on-success log subscriber templating multilink bundle-name authenticated ! license udi pid CSR1000V sn 91V3AHTVAJ1 diagnostic bootup level minimal memory free low-watermark processor 72406 ! ! spanning-tree extend system-id username ec2-user privilege 15 redundancy ! crypto keyring mykey local-address 10.60.0.89 ! local-address is the private IP address of this CSR pre-shared-key address 18.104.22.168 key Aviatrix1! ! 22.214.171.124 is the public IP address of Avaitrix ! crypto isakmp policy 10 encryption aes 256 authentication pre-share group 2 lifetime 28800 crypto isakmp keepalive 10 3 periodic crypto isakmp profile myprofile keyring mykey self-identity address match identity address 126.96.36.199 255.255.255.255 ! crypto ipsec transform-set myset esp-aes 256 esp-sha-hmac mode tunnel crypto ipsec df-bit clear ! crypto ipsec profile ipsec_profile set security-association lifetime seconds 28800 set transform-set myset set pfs group2 ! interface Loopback0 ip address 10.61.0.1 255.255.255.0 ! interface Tunnel0 ip address 169.254.48.97 255.255.255.252 ip tcp adjust-mss 1387 tunnel source 10.60.0.89 tunnel mode ipsec ipv4 tunnel destination 188.8.131.52 tunnel protection ipsec profile ipsec_profile ! interface VirtualPortGroup0 vrf forwarding GS ip address 192.168.35.101 255.255.255.0 ip nat inside no mop enabled no mop sysid ! interface GigabitEthernet1 ip address dhcp ip nat outside negotiation auto no mop enabled no mop sysid ! router bgp 65002 bgp log-neighbor-changes network 10.61.0.0 mask 255.255.255.0 neighbor 169.254.48.98 remote-as 65003 neighbor 169.254.48.98 timers 10 30 30 ! address-family vpnv4 neighbor 169.254.48.98 activate neighbor 169.254.48.98 send-community extended exit-address-family ! iox ip forward-protocol nd ip tcp mss 1387 ip tcp window-size 8192 ip http server ip http authentication local ip http secure-server ! ip nat inside source list GS_NAT_ACL interface GigabitEthernet1 vrf GS overload ip route vrf GS 0.0.0.0 0.0.0.0 GigabitEthernet1 10.60.0.81 global ip ssh rsa keypair-name ssh-key ip ssh version 2 ip ssh pubkey-chain username ec2-user key-hash ssh-rsa BF29B2896E9286C9B44DD472EF3397DA ec2-user ip scp server enable ! ip access-list standard GS_NAT_ACL 10 permit 192.168.35.0 0.0.0.255 20 permit 10.61.0.0 0.0.0.255 ! control-plane ! line con 0 stopbits 1 line vty 0 4 login local transport input ssh line vty 5 20 login local transport input ssh ! app-hosting appid guestshell app-vnic gateway1 virtualportgroup 0 guest-interface 0 guest-ipaddress 192.168.35.102 netmask 255.255.255.0 app-default-gateway 192.168.35.101 guest-interface 0 name-server0 184.108.40.206 end ip-10-60-0-89#
BGP Working Config. with address-family ipv4
The configuration above uses the vpn4 as address family. You can also make it work with ipv4 address family
router bgp 65002 bgp log-neighbor-changes neighbor 169.254.48.98 remote-as 65003 neighbor 169.254.48.98 timers 10 30 30 neighbor 169.254.238.118 remote-as 65001 neighbor 169.254.238.118 timers 10 30 30 ! address-family ipv4 network 10.61.0.0 ! 10.61.0.0 is being advertised by Cisco CSR redistribute connected neighbor 169.254.48.98 activate neighbor 169.254.238.118 activate exit-address-family !
Aviatrix Transit Gateway workflow allows direct connectivity from Transit Gateway to 3rd party devices. The standard IPSec protocols allows Aviatrix Transit Gateway to connect to any devices supporting IPSec. These devices could be in the same Public Cloud, a different Public Cloud or to the On-Prem devices.
The workflow based implementation allows ease of use and reduces time to market.
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