Tcp

本文不定期更新 :) 上个礼拜逛Hacker News看到推荐了一份写于1991年介绍TCP/IP协议的文章A TCP/IP Tutorial。 初略的扫了几眼，发现不错，加入了收藏夹。 昨天晚上抽出时间来细读了一遍觉得很有翻译的价值，于是试着翻译一下： Introduction This tutorial contains only one view of the salient points of TCP/IP, and therefore it is the “bare bones” of TCP/IP technology. It omits the history of development and funding, the business case for its use, and its future as compared to ISO OSI. Indeed, a great deal of technical information is also omitted. What remains is a minimum of information that must be understood by the professional working in a TCP/IP environment. These professionals include the systems administrator, the systems programmer, and the network manager. ...

我们一般会调整内核tcp参数以提高web服务器(比如ngin)的性能。 sysctl 加载Linux 内核配置 1 sysctl -p /etc/sysctl.d/xxx-xxx.conf meat 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 # /etc/sysctl.d/00-network.conf # Receive Queue Size per CPU Core, number of packets # Example server: 8 cores net.core.netdev_max_backlog = 4096 # SYN Backlog Queue, number of half-open connections net.ipv4.tcp_max_syn_backlog = 32768 # Accept Queue Limit, maximum number of established # connections waiting for accept() per listener. net.core.somaxconn = 65535 # Maximum number of SYN and SYN+ACK retries before # packet expires. net.ipv4.tcp_syn_retries = 1 net.ipv4.tcp_synack_retries = 1 # Timeout in seconds to close client connections in # TIME_WAIT after receiving FIN packet. net.ipv4.tcp_fin_timeout = 5 # Disable SYN cookie flood protection net.ipv4.tcp_syncookies = 0 # Maximum number of threads system can have, total. # Commented, may not be needed. See user limits. #kernel.threads-max = 3261780 # Maximum number of file descriptors system can have, total. # Commented, may not be needed. See user limits. #fs.file-max = 3261780