catalina ethernet not working

hello

system is hp pro 3500

i7 3770

240gb ssd

1.5gb hdd



realtek rtl 8171 ethernet

took me some time to install catalina on this pc <<first time done this this>>but eventually success,but the only thing is i can't find any useful information about how to make it work to have internet through ethernet connections no internet no fun

please somebody help me what i need to do.

ps on ebay i have find TP-LINK WiFi PCI Express Adapter "TL-WDN4800" for good price and now i am waiting to...

catalina ethernet not working