邮箱传输必须依赖服务器吗,三大协议与传输链路解析,邮箱传输的依赖性 三大协议及其传输链路解析
Must email transmission rely on a server? Analysis of the three major protocols and transmission links. Analysis of the three major protocols dependent on email transmission and their transmission links
以上为机器翻译结果，长、整句建议使用 人工翻译 。