Virsh Network Types

Nat

<network>
  <name>nat</name>
  <uuid>77b28eff-3186-4410-adb6-2fb0b97746b9</uuid>
  <forward mode='nat'/>
  <bridge name='virbr1' stp='on' delay='0'/>
  <mac address='52:54:00:08:29:fb'/>
  <ip address='172.16.88.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='172.16.88.2' end='172.16.88.254'/>
    </dhcp>
  </ip>
</network>

Define and start

• virsh net-define nat.xml
• virsh net-start nat

Iptables

• iptables -t nat -vnL POSTROUTING

Chain POSTROUTING (policy ACCEPT 171 packets, 10860 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 RETURN     all  --  *      *       172.16.88.0/24       224.0.0.0/24        
    0     0 RETURN     all  --  *      *       172.16.88.0/24       255.255.255.255     
    0     0 MASQUERADE  tcp  --  *      *       172.16.88.0/24      !172.16.88.0/24       masq ports: 1024-65535
    0     0 MASQUERADE  udp  --  *      *       172.16.88.0/24      !172.16.88.0/24       masq ports: 1024-65535
    0     0 MASQUERADE  all  --  *      *       172.16.88.0/24      !172.16.88.0/24