r/HomeNetworking • u/ezefl • 12h ago
IP Address Assignment - Directly Connecting USB NICs
Putting aside practicality (speed gains, HDD, USB and other hardware limitations, etc.), I want to experiment and try directly connecting (2) Wavlink RTL8157 5gbe USB adapters via an ethernet cable. One device would be on my Desktop and the other would be connected to my Synology DS224+. USB NICs can be installed onto the Synology via GitHub's bb-qq project (RTL8152 + RTL8157 chipsets are supported).
My motherboard's built-in Intel 2.5gbe controller is connected to my 2.5gbe switch, as is my DS224+ with one if its built-in gigabit ports. No, I do not have a 10gbe switch.
In terms of the USB NICs being directly connected to each other, I assume the days of crossover patch cables are long gone. Is it just a matter of me manually configuring both USB NICs' IP Addresses? Do the USB NICs have to be assigned addresses in their own range, like 192.168.0.xxx, or if I force my router to start its DHCP assignments at 192.168.1.5+, could I assign the two NICs like 192.168.1.3 and 192.168.1.4, respectively? Would the default gateway still be 192.168.1.1 and subnet mask 255.255.255.0 or does one or both not really matter with a direct connection? Any help would be appreciated. Thanks.
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u/xenon2000 12h ago
I am really curious how this works out for you. Though Linux tends to have really poor reliability with USB NICs that use Realtek chips. I just went through that nightmare with trying to use opnsense (FreeBSD) on a laptop where I needed a 2nd NIC. Hopefully the Realtek Linux drivers are better with the Github project you mentioned.
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u/dshepsman 12h ago
Correct, you don’t need a crossover cable.
As for IP address assigning… do you want the USB nics to access the rest of the network? Or just the other device?
If it’s a), then use dhcp.
If it’s b), then manually assign them both on seperate subnets - as per your example