MintUpdate says local apt-mirror is unreachable

[Tony Whelan]

Linux Mint Serena (18.1) 64 bit, and 18.2 Sonya (64 bit)

I set up a local mirror of linuxmint packages from my ISP's mirror (mirror.internode.on.net/linuxmint-packages), using the apt-mirror package. I have done so to speed up repeated rebuilds of my test machine when testing out scripts and software.

On my Serena or Sonya PCs, when I set /etc/apt/sources.list.d//etc/apt/sources.list.d to get linux mint packages from the local mirror (http://192.168.8.72/linuxmint serena main upstream import backport) I can install mint packages (eg nemo-terminal) successfully using apt from a terminal,or by using synaptic. I can browse to http://192.168.8.72/linuxmint/ and can see the mirror files as well.

However mintUpdate (Update Manager) reports that my local mirror 192.168.8.72/linuxmint is "unreachable".

I may be quite wrong, but this seems to suggest that mintUpdate is hard-wired to not recognise mirrors that aren't on a predetermined list.

If so, I guess this isn't a bug so much as a feature. But I'd really like to know if this is something that I can get around.

I have the same issue on a Sonya PC and a Serena PC. Both have been rebooted several times, no difference.

inxi -Sr on my Serena PC returns:

System: Host: HERCULES Kernel: 4.4.0-53-generic x86_64 (64 bit) Desktop: Cinnamon 3.2.7
           Distro: Linux Mint 18.1 Serena
Repos: Active apt sources in file: /etc/apt/sources.list.d/official-package-repositories.list
           deb http://192.168.8.72/linuxmint serena main upstream import backport
           deb http://mirror.internode.on.net/pub/ubuntu/ubuntu xenial main restricted universe multiverse
           deb http://mirror.internode.on.net/pub/ubuntu/ubuntu xenial-updates main restricted universe multiverse
           deb http://mirror.internode.on.net/pub/ubuntu/ubuntu xenial-backports main restricted universe multiverse
           deb http://security.ubuntu.com/ubuntu/ xenial-security main restricted universe multiverse
           deb http://archive.canonical.com/ubuntu/ xenial partner

I mention that I have not yet tested the Ubuntu packages as the local mirror is still being created (70GB).

[Tony Whelan (tony-whelan)]

I find if I add this local mirror to the additional repositories rather than the official repositories, Update Manager does not complain. The issue for me is how to get Mint to use the additional repositories in preference to the official.

[Andrew Smith (asmith22)]

I've had the same problem for a year now, with Linux Mint 20.1. There must be a way to fix it even just on my side, surely the mirror list is not set in stone somewhere?

Can anyone suggest a solution please?