IPTables blocking docker container internet access on CentOS
I have two (virtual) servers running CentOS with Docker installed.
We have installed IPTables and everything works as expected.
I then adapt the service file:
/usr/lib/systemd/system/docker.service
And set the execute command to not adjust the firewall.
ExecStart=/usr/bin/dockerd --iptables=false
Now if I start a docker container and try to curl an address I get the error
curl: (6) Could not resolve host: google.com; Unknown error
I have the following networks:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 00:23:7d:e9:c3:58 brd ff:ff:ff:ff:ff:ff
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default
link/ether 02:42:ff:62:c5:5f brd ff:ff:ff:ff:ff:ff
7: vethc4abff6@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT group default
link/ether 02:ba:1c:a3:6d:fc brd ff:ff:ff:ff:ff:ff link-netnsid 0
And IPTable rules:
iptables -A INPUT -i docker0 -j ACCEPT
iptables -A FORWARD -i docker0 -o eth0 -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
I expected this to allow internet access from the containers - and this seems to work perfectly on the other CentOS server.
What am I missing?
centos iptables docker
asked 10 mins ago
Dave AlgerDave Alger
1012
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Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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I have two (virtual) servers running CentOS with Docker installed.
We have installed IPTables and everything works as expected.
I then adapt the service file:
/usr/lib/systemd/system/docker.service
And set the execute command to not adjust the firewall.
ExecStart=/usr/bin/dockerd --iptables=false
Now if I start a docker container and try to curl an address I get the error
curl: (6) Could not resolve host: google.com; Unknown error
I have the following networks:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 00:23:7d:e9:c3:58 brd ff:ff:ff:ff:ff:ff
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default
link/ether 02:42:ff:62:c5:5f brd ff:ff:ff:ff:ff:ff
7: vethc4abff6@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT group default
link/ether 02:ba:1c:a3:6d:fc brd ff:ff:ff:ff:ff:ff link-netnsid 0
And IPTable rules:
iptables -A INPUT -i docker0 -j ACCEPT
iptables -A FORWARD -i docker0 -o eth0 -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
I expected this to allow internet access from the containers - and this seems to work perfectly on the other CentOS server.
What am I missing?
centos iptables docker
asked 10 mins ago
Dave AlgerDave Alger
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I have two (virtual) servers running CentOS with Docker installed.
We have installed IPTables and everything works as expected.
I then adapt the service file:
/usr/lib/systemd/system/docker.service
And set the execute command to not adjust the firewall.
ExecStart=/usr/bin/dockerd --iptables=false
Now if I start a docker container and try to curl an address I get the error
curl: (6) Could not resolve host: google.com; Unknown error
I have the following networks:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 00:23:7d:e9:c3:58 brd ff:ff:ff:ff:ff:ff
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default
link/ether 02:42:ff:62:c5:5f brd ff:ff:ff:ff:ff:ff
7: vethc4abff6@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT group default
link/ether 02:ba:1c:a3:6d:fc brd ff:ff:ff:ff:ff:ff link-netnsid 0
And IPTable rules:
iptables -A INPUT -i docker0 -j ACCEPT
iptables -A FORWARD -i docker0 -o eth0 -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
I expected this to allow internet access from the containers - and this seems to work perfectly on the other CentOS server.
What am I missing?
centos iptables docker
asked 10 mins ago
Dave AlgerDave Alger
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I have two (virtual) servers running CentOS with Docker installed.
We have installed IPTables and everything works as expected.
I then adapt the service file:
/usr/lib/systemd/system/docker.service
And set the execute command to not adjust the firewall.
ExecStart=/usr/bin/dockerd --iptables=false
Now if I start a docker container and try to curl an address I get the error
curl: (6) Could not resolve host: google.com; Unknown error
I have the following networks:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 00:23:7d:e9:c3:58 brd ff:ff:ff:ff:ff:ff
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default
link/ether 02:42:ff:62:c5:5f brd ff:ff:ff:ff:ff:ff
7: vethc4abff6@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP mode DEFAULT group default
link/ether 02:ba:1c:a3:6d:fc brd ff:ff:ff:ff:ff:ff link-netnsid 0
And IPTable rules:
iptables -A INPUT -i docker0 -j ACCEPT
iptables -A FORWARD -i docker0 -o eth0 -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
I expected this to allow internet access from the containers - and this seems to work perfectly on the other CentOS server.
What am I missing?
centos iptables docker
centos iptables docker
asked 10 mins ago
Dave AlgerDave Alger
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 10 mins ago
Dave AlgerDave Alger
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 10 mins ago
Dave AlgerDave Alger
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 10 mins ago
Dave AlgerDave Alger
1012
asked 10 mins ago
Dave AlgerDave Alger
1012
1012
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Dave Alger is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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