Docker web app unaccesible when no Internet connection

dhodo · 23 March 2022 10:46

Hi everyone, this is my first message on the forum!

I use docker to work on my web development but I recently discovered that I can’t access to my web apps when I am disconnected from the Internet. This is, I can work on local development without problem but as soon as I have an Internet connection. I firstly thought that this was a Dockerfile or docker-compose issue related but it is not. I’ve tried different configurations and nothing work: as soon as I disconnect the Internet I can’t access to my web app from the browser (I tried Firefox and Chrome and none of them seems to work. However, I can access to the container throughout the command line (docker exec -it…) without any problem.

This is: the containers are still up and running my it seems that my computer doesn’t know how to connect them when I disconnect the Internet cable or Wifi. May I have a wrong DNS configuration or something like this? Am I missing some docker configuration?

Thanks!

Strit · 23 March 2022 10:49

If you disconnect from the internet, you won’t have any DNS lookups available. So you should use your IP and port number in the browsers address bar, like:

http://XXX.XXX.XXX.XXXX:YYYY

dhodo · 23 March 2022 11:55

I have a lot of network interfaces that I guessed are created by docker:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp60s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether b4:45:06:a8:f4:2b brd ff:ff:ff:ff:ff:ff
3: wlp0s20f3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 12:fc:f0:3a:df:5f brd ff:ff:ff:ff:ff:ff permaddr f8:b5:4d:ff:ab:b8
4: enp0s20f0u1u4i5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 80:3f:5d:08:7a:ac brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.39/24 brd 192.168.1.255 scope global dynamic noprefixroute enp0s20f0u1u4i5
       valid_lft 38616sec preferred_lft 38616sec
    inet6 fe80::ef26:a3e7:cce9:c4b3/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
5: br-8204e69629f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:98:5b:b2:0a brd ff:ff:ff:ff:ff:ff
    inet 172.24.0.1/16 brd 172.24.255.255 scope global br-8204e69629f1
       valid_lft forever preferred_lft forever
6: br-a7ca5c5fc183: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:81:5d:dd:b9 brd ff:ff:ff:ff:ff:ff
    inet 172.19.0.1/16 brd 172.19.255.255 scope global br-a7ca5c5fc183
       valid_lft forever preferred_lft forever
7: br-bac068403217: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:db:3b:25:75 brd ff:ff:ff:ff:ff:ff
    inet 172.25.0.1/16 brd 172.25.255.255 scope global br-bac068403217
       valid_lft forever preferred_lft forever
8: br-e2199861d8d0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:87:5c:2d:d4 brd ff:ff:ff:ff:ff:ff
    inet 172.23.0.1/16 brd 172.23.255.255 scope global br-e2199861d8d0
       valid_lft forever preferred_lft forever
9: br-624d074b2192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:80:91:f7:27 brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/16 brd 172.18.255.255 scope global br-624d074b2192
       valid_lft forever preferred_lft forever
    inet6 fe80::42:80ff:fe91:f727/64 scope link 
       valid_lft forever preferred_lft forever
10: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:64:e4:2b:9b brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
11: br-e2c3dfef2f3d: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:0c:59:7b:19 brd ff:ff:ff:ff:ff:ff
    inet 172.20.0.1/16 brd 172.20.255.255 scope global br-e2c3dfef2f3d
       valid_lft forever preferred_lft forever
12: br-7662d0e60fa4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:6e:5f:37:14 brd ff:ff:ff:ff:ff:ff
    inet 172.21.0.1/16 brd 172.21.255.255 scope global br-7662d0e60fa4
       valid_lft forever preferred_lft forever
13: br-782258e777cf: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:f5:d1:c4:2f brd ff:ff:ff:ff:ff:ff
    inet 172.22.0.1/16 brd 172.22.255.255 scope global br-782258e777cf
       valid_lft forever preferred_lft forever
23: vethd9bd7b1@if22: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-624d074b2192 state UP group default 
    link/ether 32:ff:6b:be:cc:04 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::30ff:6bff:febe:cc04/64 scope link 
       valid_lft forever preferred_lft forever
25: vethe5a216a@if24: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-624d074b2192 state UP group default 
    link/ether be:a7:8b:f7:51:38 brd ff:ff:ff:ff:ff:ff link-netnsid 2
    inet6 fe80::bca7:8bff:fef7:5138/64 scope link 
       valid_lft forever preferred_lft forever
27: veth0454a05@if26: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-624d074b2192 state UP group default 
    link/ether ca:b0:c1:2a:2a:a7 brd ff:ff:ff:ff:ff:ff link-netnsid 1
    inet6 fe80::c8b0:c1ff:fe2a:2aa7/64 scope link 
       valid_lft forever preferred_lft forever
29: veth538354d@if28: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-624d074b2192 state UP group default 
    link/ether 7e:89:70:a4:5f:1a brd ff:ff:ff:ff:ff:ff link-netnsid 3
    inet6 fe80::7c89:70ff:fea4:5f1a/64 scope link 
       valid_lft forever preferred_lft forever

Besides localhost:80/… I can access to my web using this interface:

*10: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default *

link/ether 02:42:64:e4:2b:9b brd ff:ff:ff:ff:ff:ff*
inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0*

So if I write in the url: 172.17.0.1:80/… I can access too to my web app when there is Internet connection but still can’t when there is not.

I tried the rest of ips with no luck. Any idea?

Thanks!