Unable to access local network IP from docker container - macos

Question

Running macOS and docker ubuntu on it, I am unable to ping my local network's IP addresses. Below is the network configuration of my docker container. I can ping my host machine's IP address but I am unable to access other IP addresses on the local network.
root# ping 172.17.101.192
PING 172.17.101.192 (172.17.101.192) 56(84) bytes of data.
From 172.17.0.3 icmp_seq=1 Destination Host Unreachable
From 172.17.0.3 icmp_seq=2 Destination Host Unreachable
root# ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:ac:11:00:03
inet addr:172.17.0.3 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe11:3/64 Scope:Link
Is there any network configuration which would help me to perform this operation?
I have tried net=host but it is not helping it.

Answer 1

I was using docker for mac, the issue was docker internal network conflicting with my local network addressing.
To resolve the this issue, i need to go to Preferences in the dokcer menu.
In Preferences menu Daemon>Advanced Menu, i can supply other bip.
{
"bip" : "12.12.0.1/24"
}
Click apply and restart. The next time docker will start with internal network as 12.12.0.1/24.

Answer 2

I think docker internal network could be conflicting with your local network addressing.
Try to run Docker changing the default internal network to something that doesn't conflict, as 172.31.0.0/24. Add to your Docker startup options --bip 172.31.0.1/24, probably located in /etc/default/docker:
# Use DOCKER_OPTS to modify the daemon startup options.
DOCKER_OPTS="--bip 172.31.0.1/24"
UPDATE: Although this is true in Linux, Mac implementation is different, see docs here, so it depends if you're using Docker for Mac or for Linux.
Just to test, try to attach your laptop to a different network, any in the range of 192.168.0.0/16 would suffice.

Answer 3

I'm guessing you're using docker-machine.
You should check out docker for mac as it has some networking improvements that may make this work for you. This is what I'm using and I'm able to reach other hosts on my internal network from docker.

Answer 4

I tried the following, and it works:
mac-os $> ifconfig
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 78:31:c1:bd:4b:84
inet6 fe80::1425:a90d:9c00:ef53%en0 prefixlen 64 secured scopeid 0x4
inet 10.191.41.1 netmask 0xfffff800 broadcast 10.191.47.255
nd6 options=201<PERFORMNUD,DAD>
media: autoselect
status: active
So my ip is 10.191.41.1. Then I do:
mac-os $> docker run -ti --rm ubuntu bash -c "apt-get update && apt-get install -y inetutils-ping && ping 10.191.41.1"
Which installs the "ping" command, and tries to ping my host. I get the right answers:
[...]
PING 10.191.41.1 (10.191.41.1): 56 data bytes
64 bytes from 10.191.41.1: icmp_seq=0 ttl=37 time=0.303 ms
64 bytes from 10.191.41.1: icmp_seq=1 ttl=37 time=0.536 ms
[...]

Answer 5

I wanted to throw this answer out as it happened to me on Windows, but could really on any environment. I was using a bridge network on my local machine for a service I was developing and ran into similar issues, what was weird was that pinging our production physical servers (which started with a 10.10... IP pattern) or the random sites on the internet I was able to receive a response. But the physical dev server which sat on a 172.16... pattern didn't work.
Finally I discovered through doing docker network inspect on the networks I had locally that one had created with the same subnet of 172.16... which overlapped my physical server IP address range. So when I was pinging the physical dev server, it was trying to find it on the virtual docker network, where it didn't exist.
After deleting that network (it was a dev one I didn't use), everything worked.
docker network rm {networkName}
If I had to keep the network, it is possible to change the subnet in the docker-compose file. If you need to change the conflicting subnet, the link to that is here How do configure docker compose to use a given subnet if a variable is set, or choose for itself if it isn't?
That would look something like this (if you wanted a 12.12 subnet):
networks:
default:
ipam:
config:
- subnet: 12.12.0.0/16