Docker - No route to host

Question

When i try and connect to a port from within my container to another container, i am unsuccessful and get,

root@ac1590a59fe5:/opt/f5massupgrade#         


        

Answer 1

For me the problem was conflicting MAC addresses... don't know how this could happen...

Answer 2

We hit this issue on a RHEL box which was running firewalld. The firewall was preventing container to host access (other than icmp traffic).

We needed to configure the firewall to allow traffic from the docker containers through to the host. In our case, the containers were in a bridge network on subnet 172.27.0.0/16 (determined via docker network ls and docker inspect <network-name>). Firewall rules for firewalld can be updated via:

firewall-cmd --permanent --zone=public --add-rich-rule='rule family=ipv4 source address=172.27.0.0/16 accept'
firewall-cmd --reload

This was a useful reference in resolving the issue.