--- icon: material/new-box --- !!! question "Since sing-box 1.12.0" # TCP ### Structure ```json { "dns": { "servers": { "type": "udp", "tag": "", "server": "", "server_port": 53, // Dial Fields } } } ``` !!! info "Difference from legacy UDP server" * The old server uses default outbound by default unless detour is specified; the new one uses dialer just like outbound, which is equivalent to using an empty direct outbound by default. * The old server uses `address_resolver` and `address_strategy` to resolve the domain name in the server; the new one uses `domain_resolver` and `domain_strategy` in [Dial Fields](/configuration/shared/dial/) instead. ### Fields #### server ==Required== The address of the DNS server. If domain name is used, `domain_resolver` must also be set to resolve IP address. #### server_port The port of the DNS server. `53` will be used by default. ### Dial Fields See [Dial Fields](/configuration/shared/dial/) for details.