customising docker network doesn't work

Vote count:

0

This is what I'm doing:

           |CentOS Host                         |Docker container
Gateway  --|---> enp0s9 ----> br0 ---> vethA ---|-->eth0
10.0.1.1   |                                    |  10.0.1.201

1 On a CentOS host server, NIC enp0s9 connects to LAN

2 I create a bridge on the host:

 brctl add br0

 brctl stg br0 off

Then I start a docker container with --net=none.

Then manually add network to the container as a guide from docker.com.

Now the problem is gateway and container cannot ping each other.

When I ping from container to gateway, with tcpdump I can see that gateway can receive ARP Reqsest packet from container, and gateway replied ARP Reply:

12:50:20.583658 ARP, Request who-has 10.0.1.1 tell 10.0.1.201, length 46
12:50:20.583677 ARP, Reply 10.0.1.1 is-at 0a:00:27:00:00:01 (oui Unknown), length 28

But enp0s9 only hears ARP Request from container, but cannot hear ARP Reply from gateway:

23:52:14.282233 ARP, Request who-has 10.0.1.1 tell 10.0.1.201, length 28

When I ping from gateway to container, gateway can receive ARP Reply from container, but cannot receive ICMP echo reply from container:

12:53:36.661397 ARP, Request who-has 10.0.1.201 tell 10.0.1.1, length 28
12:53:36.661943 ARP, Reply 10.0.1.201 is-at 12:34:56:78:9a:bc (oui Unknown), length 46
12:53:36.661955 IP 10.0.1.1 > 10.0.1.201: ICMP echo request, id 53778, seq 17, length 64 

And enp0s9 can here ARP Request and Reply, and it doesn't hear any ICMP packet from gateway:

23:53:35.263195 ARP, Request who-has 10.0.1.201 tell 10.0.1.1, length 46
23:53:35.263464 ARP, Reply 10.0.1.201 is-at 12:34:56:78:9a:bc (oui Unknown), length 28

So looks like problem is at host's enp0s9 interface. What should I check?

By the way, the ContOS host is a VirtualBox VM. The gateway is a VirtualBox host-only interface.

asked 21 secs ago

Evan Li

2,845

customising docker network doesn't work