<p>Do you need to run it beside a VPN "OpenVPN service" ? </p>

<p>I think using below would solve the issue for clearing any unused networks by at least 1 container.</p>

<pre><code>$ docker network prune
</code></pre>

CC BY-SA 4.0
2018-08-09T18:48:00.810Z
As stated, I have no non-builtin docker networks created, so there is nothing to prune. There is no vpn service running.
Marcin
CC BY-SA 4.0
2018-08-12T11:16:56.847Z
So you may try to see the created networks and remove any unneeded networks, you may post the result for the below command.  

     #    docker network ls
lORD
CC BY-SA 4.0
2018-08-12T18:53:14.930Z
Right, there are only the three builtin networks.
Marcin
CC BY-SA 4.0
2018-08-13T13:14:02.287Z
So could you try to run prune command and retest once again ?
lORD
CC BY-SA 4.0
2018-08-13T15:53:13.250Z
Let me be clear: I have no non-built in networks to prune. You think the problem is that there a bunch of existing networks. There are not.
Marcin
CC BY-SA 4.0
2018-08-09T07:32:02.987Z
2018-08-09T07:32:02.987Z
lORD
<p>You can explore <a href="https://github.com/docker/libnetwork/blob/922cd533eac14b6e0754756c5cacf9f44af5d699/network.go#L1657" rel="nofollow noreferrer">the sources</a> to investigate concrete case. Also I explained in <a href="https://stackoverflow.com/a/60157448/3338479">this stackoverflow answer</a> why it probably happened.</p>

CC BY-SA 4.0
2020-02-10T20:27:32.627Z
2020-02-10T20:27:32.627Z
lucidyan
<h1>The problem</h1>

<p>The problem is that this happens:</p>

<pre><code>$ docker network create  alpine4
Error response from daemon: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network
</code></pre>

<p>Notwithstanding that I have <em>no</em> non-builtin docker networks created.</p>

<p>The logs suggest that these network ranges are being attempted:</p>

<pre><code>DEBU[2018-08-08T17:21:00.877120275Z] ReleasePool(LocalDefault/192.168.240.0/20)   
DEBU[2018-08-08T17:21:00.877135316Z] ReleasePool(LocalDefault/192.168.224.0/20)   
DEBU[2018-08-08T17:21:00.877162150Z] ReleasePool(LocalDefault/192.168.208.0/20)   
DEBU[2018-08-08T17:21:00.877170059Z] ReleasePool(LocalDefault/192.168.192.0/20)   
DEBU[2018-08-08T17:21:00.877176154Z] ReleasePool(LocalDefault/192.168.176.0/20)   
DEBU[2018-08-08T17:21:00.877198642Z] ReleasePool(LocalDefault/192.168.160.0/20)   
DEBU[2018-08-08T17:21:00.877204723Z] ReleasePool(LocalDefault/192.168.144.0/20)   
DEBU[2018-08-08T17:21:00.877212452Z] ReleasePool(LocalDefault/192.168.128.0/20)   
DEBU[2018-08-08T17:21:00.877220350Z] ReleasePool(LocalDefault/192.168.112.0/20)   
DEBU[2018-08-08T17:21:00.877232829Z] ReleasePool(LocalDefault/192.168.96.0/20)    
DEBU[2018-08-08T17:21:00.877243072Z] ReleasePool(LocalDefault/192.168.80.0/20)    
DEBU[2018-08-08T17:21:00.877253643Z] ReleasePool(LocalDefault/192.168.64.0/20)    
DEBU[2018-08-08T17:21:00.877264171Z] ReleasePool(LocalDefault/192.168.48.0/20)    
DEBU[2018-08-08T17:21:00.877274553Z] ReleasePool(LocalDefault/192.168.32.0/20)    
DEBU[2018-08-08T17:21:00.877284675Z] ReleasePool(LocalDefault/192.168.16.0/20)    
DEBU[2018-08-08T17:21:00.877296023Z] ReleasePool(LocalDefault/192.168.0.0/20)     
DEBU[2018-08-08T17:21:00.877307062Z] ReleasePool(LocalDefault/172.31.0.0/16)      
DEBU[2018-08-08T17:21:00.877322208Z] ReleasePool(LocalDefault/172.30.0.0/16)      
DEBU[2018-08-08T17:21:00.877333550Z] ReleasePool(LocalDefault/172.29.0.0/16)      
DEBU[2018-08-08T17:21:00.877339489Z] ReleasePool(LocalDefault/172.28.0.0/16)      
DEBU[2018-08-08T17:21:00.877350224Z] ReleasePool(LocalDefault/172.27.0.0/16)      
DEBU[2018-08-08T17:21:00.877361031Z] ReleasePool(LocalDefault/172.26.0.0/16)      
DEBU[2018-08-08T17:21:00.877367371Z] ReleasePool(LocalDefault/172.25.0.0/16)      
DEBU[2018-08-08T17:21:00.877374978Z] ReleasePool(LocalDefault/172.24.0.0/16)      
DEBU[2018-08-08T17:21:00.877382471Z] ReleasePool(LocalDefault/172.23.0.0/16)      
DEBU[2018-08-08T17:21:00.877395020Z] ReleasePool(LocalDefault/172.22.0.0/16)      
DEBU[2018-08-08T17:21:00.877405540Z] ReleasePool(LocalDefault/172.21.0.0/16)      
DEBU[2018-08-08T17:21:00.877415851Z] ReleasePool(LocalDefault/172.20.0.0/16)      
DEBU[2018-08-08T17:21:00.877426869Z] ReleasePool(LocalDefault/172.19.0.0/16)      
DEBU[2018-08-08T17:21:00.877437210Z] ReleasePool(LocalDefault/172.18.0.0/16)    
</code></pre>

<p>Even stranger, if I pick any of those subnet ranges to use as an explicit subnet range, creation works <em>just fine</em>:</p>

<pre><code>$ docker network create --subnet 172.31.0.0/16 alpine3
189ec86443c0799a298f672497aa24fb17dc725d810cd6c3917555ae6c185012
</code></pre>

<h1>The question</h1>

<p>Given the above, why can't I just create a bridge network and have docker pick a subnet range for me?</p>

<h1>Setup</h1>

<pre><code>$ dockerd --version
Docker version 18.03.1-ce, build 9ee9f40
</code></pre>

<p>Running on ubuntu 16.04 in aws. Installed using the official .deb, no special configs in place (indeed, no <code>daemon.json</code> at all)</p>

<docker><linux><networking>
Docker won't create a bridge network without being given an explicit subnet
Marcin
# Docker won't create a bridge network without being given an explicit subnet

(Asked by: username_0 on 2018-08-08)

The problem
The problem is that this happens:
$ docker network create  alpine4
Error response from daemon: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network

Notwithstanding that I have no non-builtin docker networks created.
The logs suggest that these network ranges are being attempted:
DEBU[2018-08-08T17:21:00.877120275Z] ReleasePool(LocalDefault/192.168.240.0/20)   
DEBU[2018-08-08T17:21:00.877135316Z] ReleasePool(LocalDefault/192.168.224.0/20)   
DEBU[2018-08-08T17:21:00.877162150Z] ReleasePool(LocalDefault/192.168.208.0/20)   
DEBU[2018-08-08T17:21:00.877170059Z] ReleasePool(LocalDefault/192.168.192.0/20)   
DEBU[2018-08-08T17:21:00.877176154Z] ReleasePool(LocalDefault/192.168.176.0/20)   
DEBU[2018-08-08T17:21:00.877198642Z] ReleasePool(LocalDefault/192.168.160.0/20)   
DEBU[2018-08-08T17:21:00.877204723Z] ReleasePool(LocalDefault/192.168.144.0/20)   
DEBU[2018-08-08T17:21:00.877212452Z] ReleasePool(LocalDefault/192.168.128.0/20)   
DEBU[2018-08-08T17:21:00.877220350Z] ReleasePool(LocalDefault/192.168.112.0/20)   
DEBU[2018-08-08T17:21:00.877232829Z] ReleasePool(LocalDefault/192.168.96.0/20)    
DEBU[2018-08-08T17:21:00.877243072Z] ReleasePool(LocalDefault/192.168.80.0/20)    
DEBU[2018-08-08T17:21:00.877253643Z] ReleasePool(LocalDefault/192.168.64.0/20)    
DEBU[2018-08-08T17:21:00.877264171Z] ReleasePool(LocalDefault/192.168.48.0/20)    
DEBU[2018-08-08T17:21:00.877274553Z] ReleasePool(LocalDefault/192.168.32.0/20)    
DEBU[2018-08-08T17:21:00.877284675Z] ReleasePool(LocalDefault/192.168.16.0/20)    
DEBU[2018-08-08T17:21:00.877296023Z] ReleasePool(LocalDefault/192.168.0.0/20)     
DEBU[2018-08-08T17:21:00.877307062Z] ReleasePool(LocalDefault/172.31.0.0/16)      
DEBU[2018-08-08T17:21:00.877322208Z] ReleasePool(LocalDefault/172.30.0.0/16)      
DEBU[2018-08-08T17:21:00.877333550Z] ReleasePool(LocalDefault/172.29.0.0/16)      
DEBU[2018-08-08T17:21:00.877339489Z] ReleasePool(LocalDefault/172.28.0.0/16)      
DEBU[2018-08-08T17:21:00.877350224Z] ReleasePool(LocalDefault/172.27.0.0/16)      
DEBU[2018-08-08T17:21:00.877361031Z] ReleasePool(LocalDefault/172.26.0.0/16)      
DEBU[2018-08-08T17:21:00.877367371Z] ReleasePool(LocalDefault/172.25.0.0/16)      
DEBU[2018-08-08T17:21:00.877374978Z] ReleasePool(LocalDefault/172.24.0.0/16)      
DEBU[2018-08-08T17:21:00.877382471Z] ReleasePool(LocalDefault/172.23.0.0/16)      
DEBU[2018-08-08T17:21:00.877395020Z] ReleasePool(LocalDefault/172.22.0.0/16)      
DEBU[2018-08-08T17:21:00.877405540Z] ReleasePool(LocalDefault/172.21.0.0/16)      
DEBU[2018-08-08T17:21:00.877415851Z] ReleasePool(LocalDefault/172.20.0.0/16)      
DEBU[2018-08-08T17:21:00.877426869Z] ReleasePool(LocalDefault/172.19.0.0/16)      
DEBU[2018-08-08T17:21:00.877437210Z] ReleasePool(LocalDefault/172.18.0.0/16)    

Even stranger, if I pick any of those subnet ranges to use as an explicit subnet range, creation works just fine:
$ docker network create --subnet 172.31.0.0/16 alpine3
189ec86443c0799a298f672497aa24fb17dc725d810cd6c3917555ae6c185012

The question
Given the above, why can't I just create a bridge network and have docker pick a subnet range for me?
Setup
$ dockerd --version
Docker version 18.03.1-ce, build 9ee9f40

Running on ubuntu 16.04 in aws. Installed using the official .deb, no special configs in place (indeed, no daemon.json at all)

**Tags:** docker, linux, networking


---

## 2 answers

### Answer by username_1 on 2018-08-09. Score: 2

Do you need to run it beside a VPN "OpenVPN service" ? 
I think using below would solve the issue for clearing any unused networks by at least 1 container.
$ docker network prune

> **Comments:**
> **username_0**: As stated, I have no non-builtin docker networks created, so there is nothing to prune. There is no vpn service running.  
> **username_1**: So you may try to see the created networks and remove any unneeded networks, you may post the result for the below command.         #    docker network ls  
> **username_0**: Right, there are only the three builtin networks.  
> **username_1**: So could you try to run prune command and retest once again ?  
> **username_0**: Let me be clear: I have no non-built in networks to prune. You think the problem is that there a bunch of existing networks. There are not.  

---

### Answer by username_2 on 2020-02-10. Score: 0

You can explore [the sources](https://github.com/docker/libnetwork/blob/922cd533eac14b6e0754756c5cacf9f44af5d699/network.go#L1657) to investigate concrete case. Also I explained in [this stackoverflow answer](https://stackoverflow.com/a/60157448/3338479) why it probably happened.


---

