Setting Up Networking for Multiple NICs

1: Combining DHCP and Static IP Addresses with IPv4 and IPv6

If your machine contains multiple NICs, it is recommend that you create a .network configuration file for each network interface. The following scenario demonstrates how to set one wired network interface to use a static IP address and another wired network interface to use a dynamic IP address obtained through DHCP.

Note: The following configurations are examples and you must change the IP addresses and other information to match your network and requirements.

First, create the .network file for the static Ethernet connection in /etc/systemd/network. A best practice is to match the exact name of the network interface, which is eth0 in this example. This example file also includes a DNS server for the static IP address. As a result, the configuration sets the UseDNS key to false in the DHCP column so that Photon OS ignores the DHCP server for DNS for this interface.

cat > /etc/systemd/network/10-eth0-static-en.network << "EOF"
[Match]
Name=eth0

[Network]
Address=10.137.20.11/19
Gateway=10.137.23.253
DNS=10.132.71.1

[DHCP]
UseDNS=false
EOF

Second, create the .network file for the second network interface, which is eth1 in this example. This configuration file sets the eth1 interface to an IP address from DHCP and sets DHCP as the source for DNS lookups. Setting the DHCP key to yes acquires an IP address for IPv4 and IPv6. To acquire an IP address for IPv4 only, set the DHCP key to ipv4.

cat > /etc/systemd/network/50-eth1-dhcp-en.network << "EOF"

[Match]
Name=eth1

[Network]
DHCP=yes  

[DHCP]
UseDNS=true
EOF

1 - Combining DHCP and Static IP Addresses with IPv4 and IPv6

You can combine DHCP and static IP addresses with both IPv4 and IPv6.

Examples

The following example shows how to use DHCP to allocate both IPv4 and IPv6 addresses:

[Network]
DHCP=yes

The following example shows how to use DHCP to allocate only IPv4 addresses:

[Network]
DHCP=ipv4

The following example shows how to use DHCP to allocate only IPv6 addresses:

[Network]
DHCP=ipv6

The following example shows how to use DHCP for IPv4 addresses and static IP addresses for IPv6 addresses:

[Network]
DHCP=ipv4
Address=fd00::1/48
Gateway=fd00::252

The following example shows how to use DHCP for IPv6 addresses and static IP addresses for IPv4:

[Network]
DHCP=ipv6
Address=10.10.10.1/24
Gateway=10.10.10.253

The following example shows how to use static IP addresses for both IPv4 and IPv6:

[Network]
DHCP=ipv6
Address=10.10.10.1/24
Gateway=10.10.10.253
Address=fd00::1/48
Gateway=fd00::252