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 7 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 7 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 7 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 7 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 7 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 7 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 7 mins ago
Dave AlgerDave Alger
1012
asked 7 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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