I confess, this story could be the result of some kind of misconfiguration on my part. That said, DHCP assigns the IP address for my two network printers. One is a Dell 2155cn Color MFP, the other is a monochrome Samsung ML-2850. Both have RJ-45 ports so I cable each one into the closest switch and it joins my in-house GbE network.
One IP Address Wanders, The Other Does Not
The Dell has stubbornly hung onto the same IP address pretty much ever since I set it up: 192.168.1.15. The Samsung, on the other hand, changes IP addresses every 2-3 weeks or so.
I can tell it’s wandered off when I try to print something on my production PC, and something other than the Samsung shows up as my default printer. Fortunately, Nir Sofer’s handy NetBIOS Scanner (NetBScanner) utility — shown in the lead-in graphic for this story — helps me keep up with its peripatetic wanderings through the 254 addresses theoretically available. On my local Class C Private IP subnet 192.168.1.xx, 0 and 255 are already taken (for the network and broadcast addresses, respectively). Thus, that leaves 254 possibilities left over, less addresses already allocated to other active devices on my lone subnet.
As you can see from the lead-in graphic, the Samsung currently occupies address 192.168.1.127 on the local subnet. The last time I checked, it was at address 86. The final octet is the only one that matters, because all subnet nodes share the same first three octets: 192.168.8.
Not an Eviction: Rather, a Failure at Lease Renewal. . .
I’m speculating, but the Samsung must be failing to renew its DHCP lease or something along those lines. That’s the only reason I can think of that explains why that printer’s address wanders around the free address space on a regular basis. I could go into my router and set up a static address allocation for that device. But I still haven’t gotten around to doing that, even though I know that would provide an easy fix to stop this from happening again.
In the meantime, I’ll just keep finding the new address, and re-establishing it as the basis for my default printer connection. That’s the way things go in Windows-World these days, when I have lots more interesting stuff to think about, mess with, and dig into.
Author: Ed Tittel
Ed Tittel is a 30-plus-year computer industry veteran. He’s a Princeton and multiple University of Texas graduate who’s worked in IT since 1981 when he started his first programming job. Over the past three decades he’s also worked as a manager, technical evangelist, consultant, trainer, and an expert witness. See his professional bio for all the details.