Homework 3

NAT (1/9) Network Address Translation Convert IP Address and port between private and public realm Works on network layer and transport layer

NAT (2/9) SA 192.168.0.10 SP 1234 DA 163.13.128.5 DP 5555 NAT A B 192.168.0.10 163.13.128.5 140.112.30.8

NAT (3/9) SA 192.168.0.10 SP 1234 DA 163.13.128.5 DP 5555 NAT A B Port:1234 192.168.0.10 163.13.128.5 140.112.30.8

NAT (4/9) NAT A B Port:1234 Port:5678 192.168.0.10 163.13.128.5 SA 140.112.30.8 SP 5678 DA 163.13.128.5 DP 5555 NAT A B Port:1234 Port:5678 192.168.0.10 163.13.128.5 140.112.30.8

NAT (5/9) NAT A B Port:1234 Port:5678 Port:5555 192.168.0.10 SA 140.112.30.8 SP 5678 DA 163.13.128.5 DP 5555 NAT A B Port:1234 Port:5678 Port:5555 192.168.0.10 163.13.128.5 140.112.30.8

NAT (6/9) SA 163.13.128.5 SP 5555 DA 140.112.30.8 DP 5678 NAT A B 192.168.0.10 163.13.128.5 140.112.30.8

NAT (7/9) NAT A B Port:5678 Port:5555 192.168.0.10 163.13.128.5 SA 163.13.128.5 SP 5555 DA 140.112.30.8 DP 5678 NAT A B Port:5678 Port:5555 192.168.0.10 163.13.128.5 140.112.30.8

NAT (8/9) NAT A B Port:5678 Port:5555 192.168.0.10 163.13.128.5 SA 163.13.128.5 SP 5555 DA 192.168.0.10 DP 1234 NAT A B Port:5678 Port:5555 192.168.0.10 163.13.128.5 140.112.30.8

NAT (9/9) NAT A B Port:1234 Port:5678 Port:5555 192.168.0.10 SA 163.13.128.5 SP 5555 DA 192.168.0.10 DP 1234 NAT A B Port:1234 Port:5678 Port:5555 192.168.0.10 163.13.128.5 140.112.30.8

Types of NAT Full Cone NAT Restricted Cone NAT Port-Restricted Cone NAT Symmetric NAT

Binding Life Time of NAT (1/4) When a client sends a UDP packet to public Internet, NAT will allocate a public port for the private address and port If no UDP traffic on the public port for a period, NAT will release the public port The period is “binding life time”

Binding Life Time of NAT (2/4) Client use privet port to send a UDP packet to public server NAT Client Server Port:1234 192.168.0.10 163.13.120.90 140.112.30.80

Binding Life Time of NAT (3/4) NAT will allocate a public port for 192.168.0.10:1234 NAT Client Server Port:1234 Port:5555 192.168.0.10 163.13.120.90 140.112.30.80

Binding Life Time of NAT (4/4) If no UDP traffic on the public port for a period, NAT will release the public port NAT Client Server Port:1234 Port:5555 192.168.0.10 163.13.120.90 140.112.30.80

Homework 3 了解前述四種類型NAT之運作方式與差異 設計測試NAT類型與Binding Life Time的方法並實作

Port-Restricted Cone NAT PC Internet PC Full Cone NAT Public IP PC PC Public IP Public IP Port-Restricted Cone NAT Restricted Cone NAT Private IP PC PC PC PC PC PC PC PC

測試用NAT Brand Model Firmware Type Binding Life Time SMC SMCWRB14T-G V1.07 Full Cone NAT >155 min PCI BLW-54PM Version3.0 Release00 Restricted Cone NAT 120~180 sec BRL-04R V1.0.0 Port-Restricted Cone NAT 59 sec

評分標準 書面報告 (共25%) 程式&Demo (共65%) 解釋四種類型NAT的運作方式 測試方法與架構 (須寫出詳細流程) 流程圖 Binding Life Time (10%) Full Cone NAT (15%) Restricted Cone NAT (15%) Port Restricted Cone NAT (15%) Symmetric NAT (5%)

注意事項 (1/2) 本次作業所有測試均是針對UDP 本次作業兩個人一組 書面報告字數需1500字以上 書面報告須寫上中文姓名與學號,未寫者各扣2分 書面報告電子檔請繳交.doc或.pdf檔 Binding Life Time的誤差必須在10秒以內 可以使用任何程式語言

注意事項 (2/2) Demo時當場以截止繳交日期前寄出的source code編譯執行檔 執行環境以R219電腦中可提供的為主,如使用特殊的Compiler,請自行準備執行環境 作業驗收標準以可在R219之電腦執行為準,若Demo時程式無法於 R219之電腦執行,則視同作業未完成 作業請勿抄襲 Demo 時請攜帶書面報告紙本,並於封面註明中文姓名與學號 每組 Demo 時間為15分鐘,必須於時間內完成四種NAT與Binding Life Time的測試,逾時未測試完畢的部份不予計分 Demo時所使用的NAT, Binding Life Time均小於5分鐘 作業三最高分90分 (Term-Project才有可能得到高於90分)

繳交日期 95年6月24日 24:00 前 於截止時間前將Source Code與書面報告寄至network2006@csie.ntu.edu.tw Demo地點 : R219 Demo時段 : 6/29 , 6/30 請於Demo前一週至R442門口填表預約時段 繳交格式 Source Code檔名 : 學號1_學號2.副檔名 書面報告檔名 : hw3_學號1_中文姓名1_學號2_中文姓名2.副檔名 信件標題格式 : hw3_學號1_中文姓名1_學號2_中文姓名2 未依上述格式繳交者各扣2分