On Fri, 14 Apr 2023 09:02:33 -0400
Haines Brown <haines@???> wrote:

> On Thu, Apr 13, 2023 at 07:25:34PM +0200, Didier Kryn wrote:
> > >
> > > My basic problem seems to be that my linux/printer is on one network
> > > and the Mac laptop on another.
> > >
> >     Your linux box can act as a print server if it has connections to both
> > networks. This is one of the features of Cups I don't like very much,
> > because I think it can be a security hole. But Cups offers this by design.
>
> Didier, in CUPS I had checked "Share this printer". However I don't
> see how doing so makes the printer accesible to a Mac laptop on
> another network (different routers).
>
> If the Mac is on a different network than linux box, is the only way
> to enable the Mac to access the Linux printer to provide the Mac
> with the printer's public IP address?
>

Hi,
what should help

solution 1:

Printer with IPP on port 631 =>

router1 redirect external port 631 =>
to the printer's ip address

the internet

<= the other router2 
<= the mac to print  connects
      to router1's external IP address 
      port 631 (if you have a static IP address
      or you need DynamicDNS) 

This solution is suboptimal from a privacy
point of view and exposes your printer
on the internet.

solution2:

Enable a vpn on router1
and allow vpn clients to be
able to access other computers
on router1's network (this is for sure
possible with openvpn) =>

<= connect mac to router1's external IP address   with vpn
      (if you have a static IP address or you need DynamicDNS)
      and you should see the printer.

solution3 if printer and mac are in the same room:

solution A: connect mac to printer with  a USB cable (up to 10mt).
solution B: connect mac to printer with WIFI if the printer has WIFI
solution C: connect mac to printer with a ETHERNET cable if both have
                 a spare ethernet port (which is unlikely) and connect them 
                 through a third network.

Hope this helps as inspiration.

Ciao,
Tito