Enhanced Mode
Only Surge Mac supports this feature, from version 2.1.0
Some applications may not obey the system proxy settings. Using enhanced mode can make all applications handled by Surge.
Surge will setup a TUN interface and route 198.18.0.0/16 to it. All DNS questions will get an answer with a fake IP in 198.18.0.0/16 block. (This block is reserved for future use by IANA.)
Surge TUN interface can only process TCP, UDP and ICMP traffic. Only use this feature when necessary.(UDP and ICMP traffic can't be proxied. It will passthrough like behind a NAT.)