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I want to test linux network namespace.

The current problem is I cannot connect internet in the namespace

here is my commands:

1 Create network namespace netns1, create a pair of veths (A and B) set B into namespace 

ip netns add netns1
ip link add A type veth peer name B
ip link set B netns netns1

2 create a bridge to connect veth A

brctl addbr bridge0
ip addr add 172.17.42.1/16 dev bridge0
ip link set dev bridge0 up
brctl addif bridge0 A
ip link set A up

3 In namespace, set the network

ip netns exec netns1 ip link set dev B name eth0
ip netns exec netns1 ip link set eth0 up
ip netns exec netns1 ip addr add 172.17.42.99/16 dev eth0
ip netns exec netns1 ip route add default via 172.17.42.1

When I ping google, I got this:

ping: unknown host www.google.com

How can I connect to the internet in this namespace ?

Here are some other details:

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Thank you

update 1

I also try to set the NAT:

iptables -t nat -A POSTROUTING -s 172.17.0.0/16 -d 0.0.0.0/0 -j MASQUERADE

But still unknown host

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1 Answer 1

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I'm assuming you are getting ping: unknown host www.google.com because your name resolution if failing because of the network connectivity issues mentioned below. However, you probably want to double check that this isn't just a DNS issue by pinging an IP address.

From what you've provided, it looks like you haven't added a physical interface to the network bridge. Without a physical interface on the bridge, traffic on that bridge has no way onto the rest of the network.

An alternative to adding a physical interface to the bridge, would be to turn on IP forwarding and set up NAT rules with iptables.

share|improve this answer
    
Thank you, i am trying to set NAT rules, it would be great if you can provide more details about this. –  vvilp Sep 22 '14 at 22:55
    
I try like this: iptables -t nat -A POSTROUTING -s 172.17.0.0/16 -d 0.0.0.0/0 -j MASQUERADE But still unknown host –  vvilp Sep 22 '14 at 23:28

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