无法在Docker Ubuntu容器中允许端口

Question

Want to allow a port say 4000. Ran:

root@66548e7316fc:/# sudo ufw allow 4000/tcp
WARN: initcaps
[Errno 2] iptables v1.6.1: can't initialize iptables table `filter': Permission denied (you must be root)
Perhaps iptables or your kernel needs to be upgraded.

Skipping adding existing rule
Skipping adding existing rule (v6)
root@66548e7316fc:/# 

root@66548e7316fc:/# sudo ufw status
ERROR: problem running iptables: iptables v1.6.1: can't initialize iptables table `filter': Permission denied (you must be root)
Perhaps iptables or your kernel needs to be upgraded.


root@66548e7316fc:/# service ufw status
 * Firewall is not running...                                                                  [fail] 
root@66548e7316fc:/# sudo ufw reload
Firewall not enabled (skipping reload)
root@94d82c9ba002:/# sudo ufw enable
ERROR: problem running ufw-init
/lib/ufw/ufw-init: 118: /lib/ufw/ufw-init: modprobe: not found
/lib/ufw/ufw-init: 118: /lib/ufw/ufw-init: modprobe: not found
/lib/ufw/ufw-init: 118: /lib/ufw/ufw-init: modprobe: not found
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 12
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 12
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
iptables-restore v1.6.1: iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more information.
sysctl: setting key "net.ipv4.conf.all.accept_redirects": Read-only file system
sysctl: setting key "net.ipv4.conf.default.accept_redirects": Read-only file system
sysctl: setting key "net.ipv6.conf.all.accept_redirects": Read-only file system
sysctl: setting key "net.ipv6.conf.default.accept_redirects": Read-only file system
sysctl: setting key "net.ipv4.icmp_echo_ignore_broadcasts": Read-only file system
sysctl: setting key "net.ipv4.icmp_ignore_bogus_error_responses": Read-only file system
sysctl: setting key "net.ipv4.icmp_echo_ignore_all": Read-only file system
sysctl: setting key "net.ipv4.conf.all.log_martians": Read-only file system
sysctl: setting key "net.ipv4.conf.default.log_martians": Read-only file system

Problem loading ipv6 (skipping)
Problem running '/etc/ufw/before.rules'
Problem running '/etc/ufw/after.rules'
Problem running '/etc/ufw/user.rules'

root@94d82c9ba002:/# 
sudo ufw reload
Firewall not enabled (skipping reload)

I'm already root as you see root@66548e7316fc:/# in the above command prompt.

Answer 1

For allowing a machine to connect to a container's port you should use the expose or ports Docker's property.

The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtime. You can specify whether the port listens on TCP or UDP, and the default is TCP if the protocol is not specified.

from Docker's documentation .

Or with ports :

By default, when you create a container, it does not publish any of its ports to the outside world. To make a port available to services outside of Docker, or to Docker containers which are not connected to the container's network, use the --publish or -p flag.

from here .

Also you can specify an IP address on which this port will be listening:

docker run -p 127.0.0.1:4000:4000 my container