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  1. Products
  2. Magic Transit
  3. How to
  4. Configure tunnel endpoints

Configure tunnel endpoints

Cloudflare recommends two tunnels for each ISP and data center router combination, one per Cloudflare endpoint. Cloudflare will assign two Cloudflare endpoint addresses shortly after your onboarding kickoff call that you can use as the tunnel destinations on your data center routers/endpoints.

To configure the tunnel(s) between Cloudflare and your data centers, you must provide the following data for each tunnel:

  • Tunnel name: A valid Linux interface name with 15 or less characters. The tunnel name cannot contain spaces or special characters, and the name cannot be shared with other tunnels.
  • Customer endpoint: A public Internet routable IP address outside of the prefixes Cloudflare will advertise on your behalf. These are generally IP addresses provided by your ISP. If you intend to use a physical or virtual connection like Cloudflare Network Interconnect, you do not need to provide endpoints because Cloudflare will provide them.
  • Interface address — A 31-bit subnet (/31 in CIDR notation) supporting two hosts, one for each side of the tunnel. Select the subnet from the following private IP space:
    • 10.0.0.0 – 10.255.255.255
    • 172.16.0.0 – 172.31.255.255
    • 192.168.0.0 – 192.168.255.255
    • 169.254.244.0/20
  • TTL: Time to Live (TTL) in number of hops for the GRE tunnel. The default value is 64.
  • MTU: Maximum Transmission Unit (MTU) in bytes for the GRE tunnel. The default value is 1476.
Edge routing configuration example
TunnelCustomer endpointInterface address
TUNNEL_1_IAD104.18.112.7510.10.10.100/31
TUNNEL_2_IAD104.18.112.7510.10.10.102/31
TUNNEL_3_ATL104.40.112.12510.10.10.104/31
TUNNEL_4_ATL104.40.112.12510.10.10.106/31

​​ Add tunnels

  1. Log in to your Cloudflare dashboard, and select your account.
  2. Select Magic Transit > Manage Magic Transit configuration > Configure.
  1. From the Tunnels tab, select Create.
  2. On the Add tunnels page, choose either a GRE tunnel or IPsec tunnel.
GRE tunnel
  1. On the Add GRE tunnels page, fill out the information for your GRE tunnel.
  2. (Optional) We recommend you test your tunnel before officially adding it. To test the tunnel, select Test tunnels.
  3. To add multiple tunnels, select Add GRE tunnel for each new tunnel.
  4. After adding your tunnel information, select Add tunnels to save your changes.
IPsec tunnel
  1. On the Add IPsec tunnels page, fill out the information for your IPsec tunnel.
  2. (Optional) We recommend you test your tunnel before officially adding it. To test the tunnel, select Test tunnels.
  1. To add multiple tunnels, select Add IPsec tunnel for each new tunnel.
  2. After adding your tunnel information, select Add tunnels to save your changes.

​​ Edit tunnels

  1. From Tunnels, locate the tunnel you want to modify and select Edit. To edit multiple tunnels, select the checkboxes for each tunnel and then select Edit selected tunnels.
  2. On the Edit tunnels page, fill out the fields you want to modify.
  3. (Optional) We recommend you test your tunnel before officially adding it. To test the tunnel, select Test tunnels.
  4. After adding your information, select Edit tunnels to save your changes.

Note that you cannot edit the Cloudflare endpoint associated with your tunnel.

​​ Delete tunnels

  1. From Tunnels, locate the tunnel you want to modify and select Delete.
  2. Confirm the action by selecting the checkbox and selecting Delete.

​​ Network Address Translation

After adding your tunnels, you can use Network Address Translation (NAT) to translate your private IP to your server’s IP address. NAT works by modifying network address information in a packet’s IP header as it moves across a router, which can help with load balancing and connecting private IP networks with non-registered IP addresses to the Internet.

​​ Configure Network Address Translation

  1. On the router, configure NAT from your private IP address to your server’s current IP address.
Router(config)# ip nat inside source static <LOCAL_IP> <GLOBAL_IP>
  1. On the router, specify which interfaces connect inside and outside of the network.
Router(config)# interface Tunnel A
Router(config)# ip nat outside
Router(config)# interface 0/0  /* WAN interface */
Router(config)# ip nat outside
Router(config)# interface 0/0  /* LAN interface - to the server */
Router(config)# ip nat inside
  1. When you are finished, end the configuration.
Router(config)# end