Around a decade ago, after a previous HP laserjet+ printer finally broke after two decades of use, I decided to get a network printer. This turned out to be a good solution at the time, as it allowed all the computers on our then wired local area network (LAN) to share the printer. This was true even though one of the computers, being an internet server that required a static, or at least pseudostatic, internet (IP) address, was on a different subnet from the rest.
A few years ago, we got a wireless network as the easiest way for the Au Pair to access the internet from her notebook computer. However, this meant she couldn't print, since her computer couldn't discover the printer through the wireless base station's NAT translation layer. We ended up printing her homework assignments from one of our computers.
Then Elizabeth's computer broke, and was replaced with a late model iMac. The iMac couldn't find the printer, even though it was on a wired connection on the same physical and logical local network as the printer. Elizabeth spent hours on the phone with Apple using their free initial support, and they couldn't figure out what the problem was either. We eventually concluded that the iMac no longer had the driver for the printer. When she needed to print, she used my machine.
Today my computer broke. I got a new one, but I was afraid we'd have to buy a new printer as well, since the expectation was that my new Mac, like Elizabeth's, wouldn't be able to talk to the printer.
When messing around with the printing options, though, I noticed that there was an option for specifying the IP address of a network printer. Unfortunately, the printer uses an IP address determined randomly by DHCP. We could figure out its IP address through trial and error - we know the likely subnet, so that would be no more than about 256 trials - but we'd have to do that repeatedly since the address would change on a periodic basis. We could get another pseudostatic IP address for the printer, but not only would that cost an extra $20 a month, it would be a hassle to get the printer to bind to the correct IP address, since our internet provider hands out even the pseudostatic IP addresses on a first come, first served basis.
However, my new computer has two ethernet ports. That got me to thinking about dual homing - putting my computer on two different networks. Was there a way to use that to get to the printer?
Eventually, the solution I hit on did involve dual homing, but didn't use the second ethernet port - instead, it used the wireless connection that this new computer also has. I connected the printer to one of the wired ports of the wireless base station, then connected to the wireless network from the computer. I then used the management interface of the base station to figure out the local IP address it had assigned to the printer. Entering that into my computer's printer configuration manually, I was able to print. I now think the problem with Elizabeth's iMac was not that it lacked the driver, but that its newer operating system no longer supported the old Appletalk protocol which our older Macs had used to discover the printer. If correct, that should mean that my wife's machine, which is now on the wireless network, will now be able to print - and perhaps the Au Pair's machine as well. At a minimum, I don't have to buy a new printer yet.
Meanwhile, I still have that second ethernet port. Maybe there's a way I can use it to serve streaming video again, without having it use up all my bandwidth and affecting my own computer's access to the internet.
I don't think it would work as seamlessly for us: when Elizabeth's new computer wouldn't print, it was on the same IP subnet as the printer and couldn't automatically discover it. I think this is one of those rare cases where Microsoft is better than Apple: under Jobs, Apple has been all too willing to jettison support for things developed before Jobs, such as our printer's version of Macintosh support, while Microsoft still does a reasonable job of maintaining backward compatibility. Prior to Jobs, of course, this particular issue was handled better by Macs, since we didn't need to be on the same IP subnet.
I'm actually pretty happy with our current setup, though, as it allows the server machine to use a faster wired network. The adjustments that are needed if the printer's IP changes are pretty easy, and I've changed the wireless router's settings so that won't happen often anyway.
Edited at 2011-09-24 10:20 pm (UTC)