CODEWITHSUNDEEP
ubuntudockerip
user2133558
user2133558

Reputation: 534

Can t ping my docker container outside of the host

Hi i have setup and started a docker container. When i access this container and do ifconfig, this is what i get:

eth0      Link encap:Ethernet  HWaddr 02:42:0a:32:00:02  
          inet addr:10.50.0.2  Bcast:0.0.0.0  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:387 errors:0 dropped:0 overruns:0 frame:0
          TX packets:18 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:73801 (73.8 KB)  TX bytes:1572 (1.5 KB)

eth0:1    Link encap:Ethernet  HWaddr 02:42:0a:32:00:02  
          inet addr:10.50.1.1  Bcast:10.50.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

eth0:2    Link encap:Ethernet  HWaddr 02:42:0a:32:00:02  
          inet addr:10.50.1.2  Bcast:10.50.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

eth0:3    Link encap:Ethernet  HWaddr 02:42:0a:32:00:02  
          inet addr:10.50.1.3  Bcast:10.50.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

I can perfectly ping those addresses form the host (eth0 and its virtual ips)

On the host this is the ifconfig output

br-dfd292823ec9 Link encap:Ethernet  HWaddr 02:42:1b:2b:32:c3  
          inet addr:10.50.0.1  Bcast:0.0.0.0  Mask:255.255.0.0
          inet6 addr: fe80::42:1bff:fe2b:32c3/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18 errors:0 dropped:0 overruns:0 frame:0
          TX packets:320 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1320 (1.3 KB)  TX bytes:65375 (65.3 KB)

docker0   Link encap:Ethernet  HWaddr 02:42:93:9a:5c:ea  
          inet addr:172.17.0.1  Bcast:0.0.0.0  Mask:255.255.0.0
          inet6 addr: fe80::42:93ff:fe9a:5cea/64 Scope:Link
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:23 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:2967 (2.9 KB)

eth0      Link encap:Ethernet  HWaddr ec:b1:d7:56:9d:88  
          inet addr:10.250.1.49  Bcast:10.250.255.255  Mask:255.255.0.0
          inet6 addr: fe80::f784:a7df:5e4e:ce2f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:270248 errors:0 dropped:0 overruns:0 frame:0
          TX packets:113084 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:208274777 (208.2 MB)  TX bytes:67211395 (67.2 MB)
          Interrupt:20 Memory:f7d00000-f7d20000 

eth1      Link encap:Ethernet  HWaddr 68:05:ca:3e:0c:f3  
          inet addr:192.168.108.222  Bcast:192.168.109.255  Mask:255.255.254.0
          inet6 addr: fe80::8f37:3338:32cf:ba39/64 Scope:Link
          inet6 addr: 2620:2c:40c0:c00:2d9e:8857:7d24:f4ee/64 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:94805 errors:0 dropped:1 overruns:0 frame:0
          TX packets:19184 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:36493713 (36.4 MB)  TX bytes:4842334 (4.8 MB)
          Interrupt:19 Memory:f7cc0000-f7ce0000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:11023 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11023 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:1730700 (1.7 MB)  TX bytes:1730700 (1.7 MB)

veth06b2b8e Link encap:Ethernet  HWaddr 8e:96:03:60:49:5c  
          inet6 addr: fe80::8c96:3ff:fe60:495c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18 errors:0 dropped:0 overruns:0 frame:0
          TX packets:392 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1572 (1.5 KB)  TX bytes:74749 (74.7 KB)

Now i am trying to ping those container adresses (10.50.0.2 , 10.50.1.1,...) from other machine that are in the same network as the host machine and route added to them to use the host machine as gw to access the 10.50.0.0/16 network, yet i can't ping the docker container IPs. I am using docker 17 ce and ubuntu 16.

Upvotes: 1

Views: 2213

Answers (1)

user2133558
user2133558

Reputation: 534

So i found the solution to my problem. Turns out that by doing sudo iptables -L -n i found the following

Chain FORWARD (policy DROP)
target     prot opt source               destination         
DOCKER-USER  all  --  0.0.0.0/0            0.0.0.0/0           
DOCKER-ISOLATION  all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
DOCKER     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
DOCKER     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0

So the FORWARD policy was set to DROP, meaning no traffic forwarding to my docker containers, i then did sudo iptables -P FORWARD ACCEPT and that resolved my problem.

Upvotes: 3

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