如果工作中不慎误删路由器IOS，或者升级了错误版本IOS，导致路由器不能正常启动，可以通过TFTP恢复IOS，还可以采用Xmodem方式通过console口恢复IOS。然而由于Console接口速率很
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如果工作中不慎误删路由器IOS，或者升级了错误版本IOS，导致路由器不能正常启动，可以通过TFTP恢复IOS，还可以采用Xmodem方式通过console口恢复IOS。然而由于Console接口速率很慢，很少有人会采用。（1）当路由器加载flash中IOS失败以后，开机就将进入rommon（ROM）监控模式。
（2）恢复IOS之前请确保本地主机上启动TFTP服务，并将IOS放置到正确的目录。
打开tftp软件3CDaemon，同时关闭电脑系统防火墙。
（3）路由器上配置TFTP。
准备console线和网线一条。连接线缆，就电脑com口与路由器console口连接，网线一头接电脑，一头接路由器的F0/0口（只能用F0/0，路由器没有系统，给路由器配置的IP地址默认是给F0/0口的）
（4）路由器上配置TFTP。
rommon 1 > IP_ADDRESS=10.8.3.1 //路由器以太网IP地址
rommon 2 > IP_SUBNET_MASK=255.255.255.0 //掩码
rommon 3 > DEFAULT_GATEWAY=10.8.3.134 //默认网关地址
rommon 4 > TFTP_SERVER=10.8.3.134 //TFTP服务器IP地址
rommon 5 > TFTP_FILE=c1841-adventerprisek9-mz.151-3.T2.bin //IOS文件名
rommon 6 > set //查看配置信息
IP_ADDRESS=10.8.3.1
IP_SUBNET_MASK=255.255.255.0
DEFAULT_GATEWAY=10.8.3.134
TFTP_SERVER=10.8.3.134
TFTP_FILE=c1841-adventerprisek9-mz.151-3.T2.bin
rommon 7 > tftpdnld //该命令从TFTP服务器恢复IOS
IP_ADDRESS: 10.8.3.1 IP_SUBNET_MASK: 255.255.255.0 DEFAULT_GATEWAY: 10.8.3.134 TFTP_SERVER: 10.8.3.134 TFTP_FILE: c1841-adventerprisek9-mz.151-3.T2.bin TFTP_MACADDR: 00:1f:6c:eb:a1:a8 TFTP_VERBOSE: ProgressTFTP_RETRY_COUNT: 18 TFTP_TIMEOUT: 7200 TFTP_CHECKSUM: Yes FE_PORT: 0 FE_SPEED_MODE: Auto DetectInvoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash: will be lost!
Do you wish to continue? y/n: [n]: y
Receiving c1841-adventerprisek9-mz.151-3.T2.bin from 10.8.3.134 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
File reception completed.
Validating checksum.
Copying file c1841-adventerprisek9-mz.151-3.T2.bin to flash:.
program load complete, entry point: 0x8000f000, size: 0xcb80
Format: Drive communication & 1st Sector Write OK...
Writing Monlib sectors.
.......................................................................................................
Monlib write complete
Format: All system sectors written. OK...
Format: Operation completed successfully.
Format of flash: complete
program load complete, entry point: 0x8000f000, size: 0xcb80
（5）TFTP查看IOS是否上传完成。
（6）rommon 8 > reset //重启路由器
