in windows i normaly use these
ipconfig /release
ipconfig /flushdns
ipconfig /renew
ipconfig /all
I am not sure, but I know that "ifconfig" is the equivalent to "ipconfig", so may be try
ifconfig /release
ifconfig /flushdns
ifconfig /renew
ifconfig /all
It's worth a try, nothing ventured, nothing gained
Regards,
Del