# 树莓派作为Cisco Console服务器 > 这是一个有意思的实现，对于远程管理Cisco路由器是一个解决之道。虽然现在我已经不再做网管，不再摆弄Cisco设备，不过这个实现方案还是很有借鉴意义的。 > > 记得当年在IDC机房，也曾在Linux服务器上通过USB转串口设备连接到Cisco设备上，使用`minicom`做维护。而今树莓派的低成本和灵活性，已经成为通用微型PC的解决方案。加上千奇百怪的扩展附件，能够实现以往需要专有设备才能实现的方案。 ![raspberry pi as cisco console server](/files/-M1TAKVMwu7s0FlcQv-f) 使用的软件名为`ser2net`，可以将串口通讯转为TCP网络端口： * `/etc/ser2net.conf` ``` BANNER:banner:NETWORKLESSONS.COM Terminal Server TCP port p device d rn 4001:telnet:0:/dev/ttyUSB0:9600 8DATABITS NONE 1STOPBIT banner ``` * 启动`ser2net` ``` ser2net -n ``` * 此时连接到树莓派的网络端口`4001`就可以访问到串口设备 ``` telnet 10.56.100.3 4001 ``` 如果要记录`ser2net`日志，则修改配置 ``` TRACEFILE:tr1:/var/log/ser2net/tr-p-Y-M-D-H:i:s.U 4001:telnet:0:/dev/ttyUSB0:9600 8DATABITS NONE 1STOPBIT banner tr=tr1 timestamp ``` ## 无线AP访问可以在树莓派上再安装一个无线网卡，并构建一个无线AP方便使用。 ``` sudo apt-get install hostapd ``` 修改`/etc/network/interfaces`，删除以下2行： ``` iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf ``` 然后替换成 ``` iface wlan0 inet static address 172.16.82.254 netmask 255.255.255.0 ``` 这样无线网卡就使用了静态IP地址`172.16.82.254/24`。 * 配置`hostapd`来设置AP `/etc/hostapd/hostapd.conf`配置： ``` ssid=Console wpa_passphrase=mysecurepassphrase wpa=3 ``` * 启动`hostapd` ``` sudo service hostapd start ``` * 如果要树莓派启动时启动`hostapd`责执行 ``` sudo update-rc.d hostapd enable ``` 现在树莓派就广播了无线SSID "Console"，但是此时因为没有DHCP服务哦，就需要客户端配置静态IP，所以不方便使用。为了解决这个问题，需要安装DHCP服务： ``` sudo apt-get install dnsmasq ``` * 在配置底部加上 ``` interface=wlan0 dhcp-range=172.16.82.10,172.16.82.100,12h ``` 然后启动`dnsmasq`服务 ``` sudo service dnsmasq restart sudo update-rc.d dnsmasq enable ``` ## 设置防火墙为了能够对树莓派做一个安全保护，设置iptables防火墙。编辑`/etc/iptables-rules`配置 ```bash *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -i lo -j ACCEPT -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT # LAN Rules -A INPUT -i eth0 -p tcp -m tcp --dport 4001 -j ACCEPT -A INPUT -i eth0 -p tcp -m tcp --dport 10050 -j ACCEPT # WIRELESS Rules -A INPUT -i wlan0 -p udp -m udp --dport 67 -j ACCEPT -A INPUT -i wlan0 -p tcp -m tcp --dport 4001 -j ACCEPT -A INPUT -i wlan0 -p tcp -m tcp --dport 10050 -j ACCEPT # Allow ICMP packets necessary for MTU path discovery -A INPUT -p icmp --icmp-type fragmentation-needed -j ACCEPT # Allow echo request -A INPUT -p icmp --icmp-type 8 -j ACCEPT -A INPUT -j DROP COMMIT ``` 然后加载防火墙配置 ``` sudo iptables-restore < /etc/iptables-rules ``` 为了能够在启动时加载防火墙配置，修改`/etc/network/interfaces`在网卡接口`wlan0`配置段落最后加上： ``` pre-up /sbin/iptables-restore < /etc/iptables-rules ``` ## 参考 * [Raspberry Pi as Cisco Console Server](https://networklessons.com/uncategorized/raspberry-pi-as-cisco-console-server/) * --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://huataihuang.gitbook.io/cloud-atlas-draft/develop/raspberry_pi/raspberry_pi_as_cisco_console_server.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.