Docker - No route to host : <p>When i try and connect to a port from within my container to another container, i am <strong>unsuccessful</strong> and get,</p>

<pre><code>root@ac1590a59fe5:/opt/f5massupgrade# curl -v https://172.17.0.1:6379
* Rebuilt URL to: https://172.17.0.1:6379/
* Hostname was NOT found in DNS cache
*   Trying 172.17.0.1...
* connect to 172.17.0.1 port 6379 failed: No route to host
* Failed to connect to 172.17.0.1 port 6379: No route to host
* Closing connection 0
</code></pre>

<p>From the docker host I am <strong>successful</strong>,</p>

<pre><code>[root@docker-host ~]# curl -v https://172.17.0.1:6379/0
* About to connect() to 172.17.0.1 port 6379 (#0)
*   Trying 172.17.0.1...
* Connected to 172.17.0.1 (172.17.0.1) port 6379 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
*   CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none
</code></pre>

<p>If i check the <strong>iptables</strong> I can see the issue,</p>

<pre><code>[root@docker-host ~]#  iptables -S INPUT
-P INPUT ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -i docker0 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
</code></pre>

<p>So I <strong>add</strong> the following and it all works well,</p>

<pre><code>iptables -I INPUT 4 -i docker0 -j ACCEPT
</code></pre>

<p>Am i missing something here?</p>

<pre><code>[root@docker-host ~]# docker version
Client:
 Version:         1.9.1
 API version:     1.21
 Package version: docker-common-1.9.1-40.el7.centos.x86_64
 Go version:      go1.4.2
 Git commit:      ab77bde/1.9.1
 Built:
 OS/Arch:         linux/amd64

Server:
 Version:         1.9.1
 API version:     1.21
 Package version: docker-common-1.9.1-40.el7.centos.x86_64
 Go version:      go1.4.2
 Git commit:      ab77bde/1.9.1
 Built:
 OS/Arch:         linux/amd64
</code></pre>

<p>Thanks,</p>
