packet tracer 5.3已经出来了，并已经有ubuntu和fedora版本。
新版本开始支持BGP。
Protocol Improvements
Packet Tracer now models these protocols not included in earlier versions: FTP, SMTP, POP3,PPPoE, VoIP, and BGP. CCNA-related protocols and technologies include improved models of HTTP,DNS, DHCP, TCP, and IP.
General Improvements
* Supports Microsoft Window 7 and stopped support for Microsoft Windows 2000
* Supports current LTS version of Ubuntu and Fedora and stopped support for previous versions
* Improved IPC features
* Customizable HTML Views for IP configuration and Traffic Generator in generic Wired End Device and generic Wireless End Device
* nslookup and ftp commands for end devices
* Email and FTP service for server end device
* Cisco IP Communicator, Email, PPPoE Dialer, and Text Editor desktop utilities
* HWIC-AP-AG-B module for 1841 and 2811 routers
下载地址1：
http://u.115.com/file/t5f363876c (115U盘提取码：t5f363876c)
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