Add reference to Bridge-NF

[xkjyeah]

I had issues setting up the bridge, before I realized that bridge-netfilter filtering must be turned off.

Symptoms

• Can ping external server from host
• Can ping DHCP server (in Docker) from host
• Cannot ping host from external server or vice-versa

Solution
Disable bridge netfiltering on the host.

# sysctl -w net.bridge.bridge-nf-call-iptables=0
# sysctl -w net.bridge.bridge-nf-call-ip6tables=0

Could you add this as a hint to the README?

[jpetazzo]

Wow, I never ran into that :-o

Are you sure that it was the problem, and that it wasn't a side-effect of something else?

Can you indicate which distro you are using, which kernel version, and which version of Docker?

Thank you!

[xkjyeah]

I am using Ubuntu 16.04, Docker 17.05

…

On Fri, Aug 4, 2017 at 3:58 PM, Jérôme Petazzoni ***@***.***> wrote: Wow, I never ran into that :-o Are you sure that it was the problem, and that it wasn't a side-effect of something else? Can you indicate which distro you are using, which kernel version, and which version of Docker? Thank you! — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#17 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACiTRzp0-jTQWi-JLIDS-yYN9DK10Pqeks5sUs89gaJpZM4On1yZ> .

[xkjyeah]

My uname -a: Linux daniel-VirtualBox 4.4.0-87-generic #110-Ubuntu SMP Tue Jul 18 12:55:35 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

…

On Fri, Aug 4, 2017 at 4:55 PM, Daniel Sim ***@***.***> wrote: I am using Ubuntu 16.04, Docker 17.05 On Fri, Aug 4, 2017 at 3:58 PM, Jérôme Petazzoni ***@***.*** > wrote: > Wow, I never ran into that :-o > > Are you sure that it was the problem, and that it wasn't a side-effect of > something else? > > Can you indicate which distro you are using, which kernel version, and > which version of Docker? > > Thank you! > > — > You are receiving this because you authored the thread. > Reply to this email directly, view it on GitHub > <#17 (comment)>, or mute > the thread > <https://github.com/notifications/unsubscribe-auth/ACiTRzp0-jTQWi-JLIDS-yYN9DK10Pqeks5sUs89gaJpZM4On1yZ> > . >

[jpetazzo]

I added a note in the README. Thank you for reporting this!