SOCKS is a generic proxy protocol for TCP/IP-based networking,application. SOCKS includes two (__1__),the SOCKS server and the SOCKS client. The SOCKS sever is implemented at the application layer. The SOCKS client is implemented between application and the (__2__) layer.When an application client needs to connect to an applications server,the client connects to a SOCKS proxy server.The proxy server connects to the application server instead of. The client,and (__3__) data between the client and the application server. For the application server, the proxy server is the (__4__).SOCKS is also one of the popular(__5__)to network firewalls.Because of its simplicity and flexibility,SOCKS has been used as generic application proxy in virtual private network (VPN),and for extranet applications.

(1). A.elements B.components C.services D.ctients
(2). A.transport B.transmission C.network D.datalink
(3). A.relays B.replaces C.replays D.repeals
(4). A.workstation B.user C.customer D.client
(5). A.methods B.alternatives C.choices D.replacements

solution:B A A D B

可能有输入错误，见凉！~