TL-WR841N/ND v9 lede+vpn

Hi, all
some time ago my first experience with lede was so so, on TP-Link TL-WR841N/ND v9 i first instaled lede 17.01 then deleted because i thinked its laggy AND major problem was VPN to my work didn't work. later on dd-wrt all worked like a charm. but dd-wrt is way too laggy and needs to be restarted too often .

so now i am back on lede, i have ton of knowledge in feww hours but this makes me insane, WHERE should i allow something.. We have CISCO device in work as i know, because in vpn setup i needed to enable this CHAP v1

Regards, Maris