Thu, April 19, 2018 ยท 1 min read

No internet on kvm guests.

No internet on kvm guests.

After setting up bridge network on network interface enp9s0, kvm guests had issues with accessing ssh, internet.

Current bridge configuration:

bridge name     bridge id               STP enabled     interfaces
br0             8000.001c2301fbdc       no              enp9s0

To allow kvm guests network connectivity with host net.ipv4.ip_forward should be enabled, add net.ipv4.ip_forward = 1 to /etc/sysctl.conf:

kernel.sysrq = 1
vm.swappiness=10
vm.vfs_cache_pressure=50
net.ipv4.ip_forward = 1

To make changes take effect without reboot execute sysctl -p:

sysctl -p

Depending on whether you are using firewalld or iptables they need to be adjusted.

Iptables:

iptables -I FORWARD -i br0 -j ACCEPT
iptables -I FORWARD -o br0 -j ACCEPT

Firewalld:

firewall-cmd --permanent --direct --passthrough ipv4 -I FORWARD -i br0 -j ACCEPT
firewall-cmd --permanent --direct --passthrough ipv4 -I FORWARD -o br0 -j ACCEPT
firewall-cmd --reload