is it possible to "comment out" the DHCP functionality in the Ethernet library for the W5110 to save memory space?
In my project memory gets low using a Nano and ethenet board.
I'd think if you use a static IP then the DHCP code should be optimized out by the compiler but that's not based on an examination of the library code.
If you're using W5100 and are running out of memory, you might consider using Library Manager (Sketch > Include library > Manage libraries...) to roll back to Ethernet version 1.1.2. Although the 2.0.0 version of the library has some really great improvements, it does use significantly more memory in some cases. The most important improvements of the 2.0.0 version are support for W5200 and W5500 but if you're using W5100 then you don't need that. There are some other improvements that would be a shame to miss out on so I do recommend that people use the 2.0.0 version if they can.