Docker shell lag problems on coffee shop wifi
Jul 26, 2017 · 1 min read
If your Docker shell starts being slow suddenly and you’re in a coffee shop…
chances are that you’re on their wifi, such as The Cloud here in the UK & it is trying to resolve a DNS entry that doesn’t exist.
Run:
sudo tcpdump -A -s0 -nni en0 port 53then run your Docker command again & the tcpdump output will probably show:
[snip].........localunixsocket.thecloud.co.uk...[snip]
appearing in the output. It’ll be trying to resolve this route & won’t be able to:
▶ dig localunixsocket.thecloud.co.uk
; <<>> DiG 9.8.3-P1 <<>> localunixsocket.thecloud.co.uk
;; global options: +cmd
;; connection timed out; no servers could be reachedIf this is the case, then you need to add:
127.0.0.1 localunixsocket.thecloud.co.ukto /etc/hosts.
Thanks to @jewilmeer on GitHub for the hint.
