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虽然ddwrt上已经自带了关联动态ip到no-ip.com的选项，但发现它关联的ip和ip138.com上查到的不一致，而ip138上的却是正确的，于是只好自己写段脚本来更新no-ip.com上的动态ip地址了，顺便加上了把新ip发送到指定邮箱功能。
假设python装在了/opt下，ddnslib.py放在了/jffs目录下，计划每两小时检测一次，那么路由器里面的cron是这么写的（注意在dd-wrt上，cron执行时的环境变量和ssh登录上后的环境变量不一样，所以要加上python可执行程序的绝对路径）：
0 */2 * * * root /opt/bin/python2 /jffs/ddnslib.py
ddnslib.py 完整代码
#!/usr/bin/env python2# coding:utf-8import httplibimport base64import stringimport datetimeimport smtplib__version__ = '0.1'__author__ = 'liaodunxia@gmail.com'class DDNS(): def __init__(self): pass def updateNoIP(self,username,password,hostname,ipaddr): """ update ip to no-ip.com """ auth = 'Basic '+base64.b64encode(username+':'+password).strip() agent = 'ddnslib.UpdateNoIP'+'/'+__version__+' '+__author__ headers = {'Authorization':auth,\ 'User-Agent':agent} conn = httplib.HTTPConnection('dynupdate.no-ip.com') conn.request(method = 'GET',\ url = '/nic/update?hostname='+hostname+'&myip='+ipaddr,\ headers = headers) resp = conn.getresponse() if resp.status == 200: print 'Successfully updated',ipaddr,'to',hostname else: print 'Update failed for',hostname,'with',resp.status,resp.reasonclass WANIP(): def __init__(self): pass def getIPFrom138(self): """ get WAN IP from ip138.com """ conn = httplib.HTTPConnection("iframe.ip138.com") conn.request("GET","/ic.asp") resp = conn.getresponse() if resp.status == 200: data = resp.read() ipaddr = data[string.find(data,'[')+1:string.find(data,']')] else: print 'getIPFrom138 failed with',resp.status,resp.reason ipaddr = '1.1.1.1' return ipaddrclass MailIP(): def __init__(self): pass def sendFrom163(self,sender,password,receiver,subject,content): """ send mail from 163.com """ server = 'smtp.163.com' port = 25 # append send time to the subject sendtime = '@'+datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S') # remove domain suffix atindex = string.find(sender,'@') username = sender if atindex != -1: username = sender[:atindex] mailfrom = username + '@163.com' smtp = smtplib.SMTP() print smtp.connect("%s:%s" % (server,port)) print smtp.docmd("HELO",server) print smtp.docmd("AUTH LOGIN") print smtp.docmd(base64.b64encode(username)) print smtp.docmd(base64.b64encode(password)) print smtp.docmd("MAIL FROM:","<%s>" % mailfrom) print smtp.docmd("RCPT TO:","<%s>" % receiver) print smtp.docmd("DATA") data = """from: %sto: %ssubject: %s #there must be at least two blank lines below subject, #or mail body would be swallowed%s .""" % (mailfrom,receiver,subject+sendtime,content) print smtp.docmd(data) smtp.quit() print "mail sent"class FileIP(): def __init__(self): pass def isIPChanged(self,currIP): ret = False with open('/tmp/ddns.ip','a+') as f: prevIP = f.read() print 'prevIP='+prevIP,'currIP='+currIP if prevIP == '' or prevIP != currIP: f.seek(0,0) f.truncate() f.write(currIP) ret = True f.close() return retif __name__ == '__main__': print 'ready to working ...' ipaddr = WANIP().getIPFrom138() print ipaddr if FileIP().isIPChanged(ipaddr): print 'ip changed' MailIP().sendFrom163('your163mailid','your163mailpass','rcvNewIPmailid@domain.com',\ 'IP='+ipaddr,'test mail') DDNS().updateNoIP('yourNoIPaccount','yourNoIPpass',\ 'yourNoIPhostname.no-ip.org',ipaddr) else: print 'ip not changed' 测试输出：
root@n13u:/jffs# ./ddnslib.py ready to working ... 222.44.176.139 prevIP= currIP=222.44.176.139 ip changed (220, '163.com Anti-spam GT for Coremail System (163com[20121016])') (250, 'OK') (334, 'dXNXXXXhbWU6') (334, 'UGFXXXXvcmQ6') (235, 'Authentication successful') (250, 'Mail OK') (250, 'Mail OK') (354, 'End data with <CR><LF>.<CR><LF>') (250, 'Mail OK queued as smtp1,C9GowXXXXXLTtgJRWEgEAg--.6418S2 1359132371') mail sent Successfully updated 222.44.176.139 to yourNoIPhostname.no-ip.org root@n13u:/jffs# ./ddnslib.py ready to working ... 222.44.176.139 prevIP=222.44.176.139 currIP=222.44.176.139 ip not changed root@n13u:/jffs#如何在dd-wrt路由器上安装python请参照下文
启用刷了dd-wrt的无线路由器asus-n13u-b1外置usb存储支持，安装python2.7
http://blog.csdn.net/t0nsha/article/details/8522814
REF:
No-IP DNS Update APIhttp://www.noip.com/integrate/request