https://linux-kvm.org/api.php?action=feedcontributions&feedformat=atom&user=Setiawan 2026-04-29T22:19:52Z User contributions MediaWiki 1.39.5 https://linux-kvm.org/index.php?title=UbuntuNetworking&diff=4623 2013-01-23T06:52:22Z

<p>Setiawan: </p> <hr /> <div>= Setting up NAT with KVM in Ubuntu =<br /> <br /> Normally, the best way to do guest networking is by setting up a bridge. However, if you use a wireless card, are frequently switching network interfaces or using VPN, or for other reason want to do NAT, then this outlines the easiest way to set it up with Ubuntu. The setup here is very similar to what [http://www.libvirt.org libvirt] uses for QEMU networking. <br /> <br /> == Install Dependencies ==<br /> <br /> sudo apt-get install bridge-utils dnsmasq<br /> <br /> == Check Kernel Modules ==<br /> <br /> Make sure that all of the following modules are around: either built in to the kernel or loadable. If you are running a plain distribution kernel, you should have all of these around without doing anything extra.<br /> <br /> # lsmod<br /> Module Size Used by<br /> tun 15616 0 <br /> bridge 64104 0 <br /> llc 11504 1 bridge<br /> xt_state 5248 1 <br /> ipt_MASQUERADE 6720 1 <br /> iptable_nat 10512 1 <br /> nf_nat 24344 2 ipt_MASQUERADE,iptable_nat<br /> nf_conntrack_ipv4 21776 3 iptable_nat <br /> nf_conntrack 76688 5 xt_state,ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4<br /> <br /> == Enabling ip forwarding ==<br /> <br /> Add the following line to the bottom of &lt;code&gt;/etc/sysctl.conf<br /> net.ipv4.ip_forward=1<br /> <br /> == Configuring a bridge ==<br /> <br /> Add the following to the bottom of &lt;code&gt;/etc/network/interfaces&lt;/code&gt;<br /> <br /> auto br0<br /> iface br0 inet static<br /> address 10.0.1.1<br /> netmask 255.255.255.0<br /> network 10.0.1.0<br /> bridge_stp off<br /> bridge_maxwait 5<br /> bridge_ports none<br /> pre-up iptables-restore &lt; /etc/iptables.up.rules<br /> <br /> == Installing config files ==<br /> <br /> # Copy [[Media:dnsmasq.conf|dnsmasq.conf]] to &lt;code&gt;/etc/dnsmasq.conf&lt;/code&gt;<br /> # Copy [[Media:iptables.up.rules|iptables.up.rules]] to &lt;code&gt;/etc/iptables.up.rules&lt;/code&gt;<br /> # Copy [[Media:qemu-ifup|qemu-ifup]] to &lt;code&gt;/etc/qemu-ifup&lt;/code&gt; and change permissions to &lt;code&gt;755&lt;/code&gt;</div>

Setiawan