I am also facing similar issue with my VPN client on BigSur. However no issues seen on Catalina. I have posted it here: https://developer.apple.com/forums/thread/677032 Can someone please tell if there is any workaround on this?

Thanks Matt for your reply. This is ruoghly how we are storing DNS settings: tun_dns_config = [[NEDNSSettings alloc]initWithServers:dns_servers]; tun_dns_config.matchDomains = match_domains; tun_dns_config.searchDomains = search_domains; Where dns_servers, match_domains and search_domains are NSString NSArrays. Things are working fine on Catalina (except for Safari browser), On BigSur DNS doesnt seem to work at all. Thanks.