Juniper防火墙丢失ScreenOS的灾难恢复
Juniper的防火墙是一台硬件防火墙，有硬件系统也有软件系统也就是ScreenOS，硬件会出故障软件自然也会出故障，在实际使用中我就碰到过多次Juniper防火墙ScreenOS丢失的情况，大多数情况是因为突然断电造成的。
下面就介绍一下如何在丢失ScreenOS的情况下重新安装ScreenOS。
将PC机与防火墙用console线和网线相连接。
断电重启防火墙，在命令行提示有Hit any key to run loader时，按任意键进入Loader。
根据提示，输入Boot File Name、Self IP Address和TFTP IP Address。同时打开TFTP软件，设置好下载目录。
重启后在超级终端会出现如下提示：
NetScreen NS-5GT Boot Loader Version 2.1.0 (Checksum: 61D07DA5)
Copyright (c) 1997-2003 NetScreen Technologies, Inc.
Total physical memory: 128MB
Test - Pass
Initialization.... Done
Hit any key to run loader
Hit any key to run loader
Hit any key to run loader
敲击任意键进入设置界面
Serial Number [0064042006003887]: READ ONLY
HW Version Number [1010]: READ ONLY 3
Self MAC Address [0014-f695-75e0]: READ ONLY
Boot File Name [ns5gt.5.0.0r8.1]: ns5gt.5.4.0r1.0
//输入你你ScreenOS文件名
Self IP Address [192.168.1.1]: 192.168.3.1
//设置防火墙trust口的ip地址
TFTP IP Address [192.168.1.254]: 192.168.3.180
//输入你pc机的ip地址，也就是你tftp的地址
Save loader config (56 bytes)... Done
Loading file "ns5gt.5.4.0r1.0"...
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Loaded Successfully! (size = 9,832,696 bytes)
Ignore image authentication!
Save to on-board flash disk? (y/[n]/m) Yes!
//确认下载ScreenOS
Saving system image to on-board flash disk...
Done! (size = 9,832,696 bytes)
Run downloaded system image? ([y]/n) Yes!
//确认执行新的ScreenOS
Start loading...
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安装好ScreenOS之后重启防火墙，这样就完成了ScreenOS的回复，一般来说原有的配置应该还会在，如果配置也丢失了，可以讲以前保存过的配置文件导入。