Although many research efforts have been devoted to the network congestion against an increase of the Internet traffic, there has been a little concern on improvement of the performance of Internet hosts in spite of the projection that the bottleneck is now being shifted from the network to hosts. We have proposed SSBT (Scalable Socket Buffer Tuning), which is intended to improve the performance of Web servers by maintaining their resources effectively and fairly, and validated its effectiveness through the simulation and implementation experiments. In the current Internet, however, a significant amount of Web document transfer requests are through HTTP proxy servers. Accordingly, in this paper, we propose a new resource management scheme for proxy servers to improve their performance and to reduce Web document transfer time via the proxy servers. Our proposed scheme has the following two components. One is an enhanced EATBT, which is an enhancement version of our previous SSBT for proxy servers by taking account of different characteristics among TCP connections. The other is a scheme that manages persistent TCP connections at proxy servers to avoid newly arriving TCP connections from being rejected due to lack of resources. We validate an effectiveness of our proposed scheme through simulation experiments, and confirm that it can manage proxy server resources effectively.