3

I'm firewalling an Ubuntu Core 16.04 host: What port does snap package management require to be opened?

I spent ages Googling this: Snapcraft's docs don't detail the port nor did any other forums. Couldn't use tcpdump to derive the required port as snap find tcpdump gave no joy.

In the end, I had to packetsniff on the router. I'll provide the answer to hopefully save others firewalling Ubuntu Core hosts the same exercise in frustration...

5

In addition to allowing DNS of course, Ubuntu Core requires TCP/443 connectivity for snap package management to check for updates & install packages. The Ubuntu Core host on 192.168.1.26 is using a port from the Dynamic/Private port range, TCP/35234

Packet Sniff Capture

Doing a host lookup of host 91.189.92.20 reports the remote IP as Snapcraft's:

20.92.189.91.in-addr.arpa domain name pointer api.snapcraft.io.

Anyhoo, hope this saves others some time-

1

I've been having the same issue and had to add the following domains to be able to establish http(s) connections:

api.snapcraft.io 
public.apps.ubuntu.com 
snapcraft.io 
fastly.cdn.snapcraft.io

At least, it was working after adding the fourth one.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.