T420 + external PCIe network card?

[thinkquan]

Has anyone tried to use an external PCIe network card via the Expresscard slot on a T*20 Thinkpad? I've seen some adapters to do eGPU via the Expresscard slot, along with at least one video on Youtube of it successfully running on a Thinkpad. However, I'd like to know if network cards will also work in these adapters.

I'd like to turn a T420 into a pfSense/OPNsense router. There are single port Expresscard Gigabit NICs available, however, running a quad port NIC, if at all possible, would be beneficial.

[axur-delmeria]

If all you need is a second LAN port, then an Expresscard Ethernet card is all you need.

As for using the eGPU setup for a quad-port gigabit LAN card,I think it would work. Still needs an external power source though.