A Stream-based Mail Proxy with Interleaved Decompression and Virus Scanning

• Main Authors: Szu-Hao Chen, 陳思豪
• Other Authors: 林盈達
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/00103262842020342479

碩士 === 國立交通大學 === 資訊科學系所 === 93 === Anti-virus systems nowadays might operate on access gateways for centralized management and early blocking viruses. When serving a group of computers, the traditional storage-based mechanism has the scalability problem due to its storage of mails under processing. This work designs a stream-based mail proxy which processes the mail segment by segment without the storage of the entire mail and interleaves the MIME parsing, decoding, decompression and virus scanning. We integrate and modify several existing open-source packages into the proxy and use the system call select to achieve single-process concurrency. The benchmarking reveals our proxy is seven times faster than in the storage-based mail proxy on simply forwarding, and three times faster on virus scanning, and twice faster on both virus scanning and decompression. Our proxy keeps constant memory consumption for each connection and works without disk storage while the disk usage of AMaViS is proportional to both the number of clients and the mail size.