網路管理實務

網路管理實務 ===== # Syllabus # Course ## DNS ### DNS - Nesting - Root: . - Each subtree: domain - Domain can divide to subdomain - Managed by [ICANN](https://www.icann.org/) - DNS namespace ![](https://i.imgur.com/gP38bgh.png) - Implementation of DNS: BIND, JEEVS, Microsoft - Domain Level - Top level, First level (child of root) - country-code top-level domains (ccTLD) (.tw) - infrastructure top-level domain (ARPA) - generic top-level domains (gTLD) - ... - Second level (child of top level) - name limit - 63 char for each - 255 char for complete name - name space - gTLDs: com, edu, gov, net, org, ... - sTLD (sponsored): 有人買了，在提供出來 - contry code TLD - Zone - Forward Zone files - hostname to address mapping - bsd1 IN A 140.113.253.131 - Reverse Zone file - address to hostname mapping - 131.253.113.140 IN PTR bsd1.nctu.edu.tw - 1.235.113.140.in-addr.arpa. ### BIND - Three major components - named - Authoritative: - Master - Slave - Nonauthoritative: - Catch - Stub: 不是internet再用的網域名稱 - Recurisive: do query for you until it return an answer or error - Forward: 把 query 的 loading 給別人 (only for Recur) ![](https://i.imgur.com/WQaPeWZ.png) - Catch - Positive catch - Negative catch (沒有回應就被 catch 起來)(避免一直要求失敗的 request) - Root server is in a list in every DNS server - Some ways to arrang DNS server ![](https://i.imgur.com/YO7PYC6.png) - library routines - command - DNS Database - text files - Resource Records (RR) - Parser commands - Command - $ORIGIN - $INCLUDE - $TTL - $GENERATE - formate: - [name] [ttl] IN [type] [data] - ; (comment) - @ (current domain name) - () (allow data to spam line) - \* (wild card) - type of rescourse - zone: SOA(是否被改動), NS(DNS server 有幾台) - Record - A : ip - PTR : 反解 - MX : - 其他 - SOA ![](https://i.imgur.com/TF3haPK.png) - csns.cs.nctu.edu.tw. (. 一定要加!!) - root.cs.nctu.edu.tw. 會自動翻成 root@cs.nctu.edu.tw - NS: Name Server - PTR: 反解 (FQDN 正反解要一致) - MX: Mail exchanger - CNAME: 轉網址 (最多轉 8 層) - TXT: arbitrary text - SRV: Specify the location of services within a domain - GSLB... - named option - notify: set notify to others(slave or DNS server) when dns change) - also-notify: notify one not in NS list - allow-recursion (開了話可能可以被別人拿來DDOS) - query-source - forwarders - allow-query - allow-transfer - blackhole - fransfer-format: 傳紀錄 - transfer-in / out: 同時間最多可以有多少run傳進來 - zone - type - master - slave - domain_name 是條件式，條件符合才會進行下面的設定 - allow-query - allow-transfer - allow-update ## Web ### Web Hostin HTML ```htmlmixed= <!DOCTYPE html> <html> <head> <title>hi</title> </head> <body> <h1>hi</h1> </body> </html> ``` - HTTP - TCP based protocol - HTTPS (with SSL) - URL (檔名有分大小寫) - Client - Server - Http response code - Content - action - get - post - headers - Authentication - URL Redirection - cookies - Content information (type, date, size, encoding, …) - Cache control - status - headers - data - CGI (Common Gateway Interface) ![](https://i.imgur.com/Puk1fVy.png) - virtual host - ip-base - name-base - Proxy - 正向 forward - cache - 反向 backward - reverse proxy - load balancing - service health check - compression - SSL ## How to host Server / Data Center ## FAMP ### Web Server - Nginx 可以承受更多的 DDOS - 只要是動態語言就丟出去處理 - Memory usage apache > nginx - Requests per second nginx > apache - How do you need to test for web server - Throughput - L4 - L7 content (e.g. http, mail) - Concurrent Sessions - Connections per second(CPS) - L4 CPS - L7 CPS - SSL CPS (加解密) - Requests per second (RPS) - L4 - L7 對內容做事情 - Other Server - WAS (銀行業) - SAP () - IIS - Oracle WebLogic - Google Servers - Tomcat - Node.js

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