A communication system includes a user plane function (UPF) configured to receive a domain name system (DNS) query from a user equipment (UE). The DNS query includes a first destination address of a first DNS server. The DNS query is for determining an address of a data server in proximity to the UE. According to the first destination address of the first DNS server, the UPF obtains, from a session management function (SMF), a second destination address of a second DNS server for providing the address of the data server. The SMF is configured to provide, to the UPF, the second destination address of a second DNS server.