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Static routes
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Static routes

Static routing is a type of routing in which routes are specified explicitly when configuring a network interface on a server or router.

To configure static routing, Write static routes on the server.

Examples of problems that can be solved using static routing:

Write static routes on the server⁠

  1. Connect to the server.

  2. Open the network interfaces configuration file with the vi text editor:

    vi /etc/netplan/01-netcfg.yaml

  3. At the end of the parameter block for the desired network interface, add a route:

    routes: 
    - to:  <ip_address>/<mask>
      via: <gateway>

    Specify:

    • <ip_address> — subnet to which you want to route;
    • <mask> — subnet mask of the subnet to which you want to route;
    • <gateway> — The gateway for the subnet of the current server, such as the gateway that is listed on the global router. The gateway address must be on the same subnet as the server.

  4. If you need to prescribe multiple routes, add them sequentially in the same block, for example:

    routes:
    - to:  192.168.0.0/28
      via: 172.16.0.1
    - to:  192.168.1.0/28
      via: 172.16.0.1

  5. Exit the vi text editor with your changes saved:

:wq

  1. Check the routing configuration:

    sudo netplan try

  2. Apply the changes:

    netplan apply

Example of organizing static routes to connect dedicated servers and a cloud server over a private network⁠

Purpose of customization⁠

Connect the two dedicated servers in the SPB-2 pool and the cloud server in the ru-2 pool with a private network using a global router and configure routing in the network so that the devices see each other.

What you need to customize⁠

In the example, we used two dedicated servers in the SPB-2 pool with access to the private network and a cloud server in the ru-2 pool for configuration.

Customization result⁠

Private connectivity will be configured between the two dedicated servers in the SPB-2 pool and the cloud server in the ru-2 pool.

Customization steps⁠

  1. Create a global router.

  2. Connect private subnets to the global router:

    • 192.168.0.0/28 to the VLAN that contains the dedicated servers in the SPB-2 pool;
    • 172.16.0.0/28 for the cloud platform project in the ru-2 pool.

  3. Assign IP addresses from the private subnets that you have connected to the global router to the dedicated servers and cloud server. For more information, see the subsection Assign IP addresses to servers.

  4. Spell out the routes:

    • at each dedicated server in the SPB-2 pool to the subnet. 172.16.0.0/28 through the gateway 192.168.0.1;
    • on cloud server in the ru-2 pool to the subnet 192.168.0.0/28 through the gateway 172.16.0.1.

Example of organizing static routes to route Internet traffic through a firewall⁠

Purpose of customization⁠

Direct Internet traffic to a dedicated server through a firewall.

What you need to customize⁠

In the example, we used a dedicated server with access to a private network and a firewall for the configuration.

Customization result⁠

Once the routed networks are set up, Internet traffic to the dedicated server will pass through the firewall.

Customization steps⁠

  1. Write a static route on a dedicated server to the subnet 0.0.0.0/0 through the gateway 198.51.100.1.

  2. Specify a default gateway on the firewall 203.0.113.2.

  3. To have internet access on a dedicated server behind a firewall, file a ticket with a request to add a static route to the Selectel router. Specify in the ticket:

    • the private subnet of the dedicated server, which is behind the firewall, in the example — 198.51.100.0/28;
    • the public IP address of the firewall, in the example — 203.0.113.2.

  4. Wait for a Selectel employee to respond that a static route is assigned to the router.

Example of organizing static routes for communication with external infrastructure through a firewall⁠

Purpose of customization⁠

Connect two dedicated servers in pools MSK-1 and SPB-2 to the external infrastructure with a private network. Using a global router, configure routing in the network so that devices see each other and route routed network traffic through the firewall in pool SPB-3.

What you need to customize⁠

In the example, we used two dedicated servers in pools MSK-1 and SPB-2 with access to a private network, a firewall in pool SPB-3, and an external infrastructure for the configuration.

Customization result⁠

Private connectivity will be configured between the external infrastructure and servers in pools MSK-1 and SPB-2, with routed network traffic passing through the firewall in pool SPB-3.

Customization steps⁠

  1. Create a global router.

  2. Connect the subnets to the global router:

    • 192.168.11.0/24 to the VLAN on which the dedicated server in the MSK-1 pool resides;
    • 192.168.22.0/24 to the VLAN on which the dedicated server in the SPB-2 pool resides;
    • 192.168.33.0/24 to the VLAN that contains the firewall in the SPB-3 pool.

  3. Assign IP addresses from private subnets that you have connected to the global router to dedicated servers. For more information, see the subsection Assign IP addresses to servers.

  4. Assign an IP address from the private subnet you connected to the global router to the firewall.

  5. Write routes on the servers:

    • in the MSK-1 pool — in the subnet. 192.168.22.0/24 и 192.168.33.0/24 through the gateway 192.168.11.1;
    • in the SPB-2 pool on the subnet. 192.168.11.0/24 и 192.168.33.0/24 through the gateway 192.168.22.1;

  6. Write the routes on the firewall — in the subnetwork 192.168.11.0/24 и 192.168.22.0/24 through the gateway 192.168.33.1.

  7. Configure routing on the global router — specify a static route for outgoing traffic to the Internet. Specify:

    • destination subnet 0.0.0.0/0;
    • Next hop — IP address of the firewall, in the example 192.168.33.2.