How do I configure an interface to have both a DHCP address and a static address in Ubuntu?

Question

In a lab setup, I want eth0 on a Ubuntu server box to get a DHCP address for talking to the outside world, and I also want to assign it a static 10.x.y.z address for talking to other boxes on the local network that have 10.x.y.z addresses. I want to do this by editing /etc/network/interfaces.

The man page for /etc/network/interfaces is modeled after "here's a bunch of examples, I hope you can figure out the actual rules on your own". I don't see a way to give one interface two addresses using two different methods (static and dhcp), and initial fumbling didn't produce useful results.

score 4 · Accepted Answer · edited Feb 06 '11 at 18:20

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You use eth:N notation for that.

auto eth0
iface eth0 inet dhcp

auto eth0:0
iface eth0:0 inet static
        address 192.168.32.10
        netmask 255.255.255.0

edited Feb 06 '11 at 18:20

Paul Hoffman

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answered Feb 06 '11 at 04:20

poige

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Errrr, could you say a bit more than that? I see nothing about that in the man page. – Paul Hoffman Feb 06 '11 at 04:30
Do you see "eth0" section in config? You can add "eth0:1" section as well. – poige Feb 06 '11 at 04:38
+= And even "eth0:0", since it's numbered from zero. – poige Feb 06 '11 at 04:50
I added an example that demonstrates what poige mentioned. Though I have never actually used this myself. – Zoredache Feb 06 '11 at 05:03
@Zoredache, you've left no chances of discovery to Paul. :-) – poige Feb 06 '11 at 05:21
I cleaned up the example a bit more to make it clear that the first entry for the interface doesn't use the : notation, but the rest do. Many thanks! It is quite sad that ":" isn't even hinted at in the man pages. – Paul Hoffman Feb 06 '11 at 16:20

user1686 · Answer 2 · 2011-02-06T16:50:01.793

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ip can add multiple addresses to an interface.

iface eth0 inet dhcp
    up ip addr add 192.168.32.10/24 dev eth0

edited Feb 06 '11 at 16:50

answered Feb 06 '11 at 12:13

user1686

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The question was about adding multiple methods, not just multiple addresses. – Paul Hoffman Feb 06 '11 at 16:20
@Paul: I just tried, and it _does_ add DHCP + static to eth0. – user1686 Feb 06 '11 at 16:50

How do I configure an interface to have *both* a DHCP address and a static address in Ubuntu?

2 Answers2

How do I configure an interface to have both a DHCP address and a static address in Ubuntu?