WAN IP address from Ubiquiti EdgeRouter ER-X

I got myself a new router, an Ubiquiti EdgeRouter ER-X , and when I tried to apply my old methods from the WNR2000v5 I discovered that the web pages returned were full of javascript. I could not find any WAN values in the files.

And that was just as well, the edge router features a full OS, with python pre installed! I set it up with eth4 as the WAN port.

The only caveat was the

show interfaces ethernet eth4 brief

did not work in a script. The command

/opt/vyatta/bin/vyatta-op-cmd-wrapper show interfaces ethernet eth4 brief

has to be used for it to work.

So after setting it up to run via crontab with the command

sudo -e crontab

the script were up and running.

The working python script:

#!/usr/bin/python

import re, os, ftplib, pickle, StringIO

def touch(fname, times=None):
        with open(fname, 'a'):
                        os.utime(fname, times)

cmd_path = '/opt/vyatta/bin/vyatta-op-cmd-wrapper'
cmd_res = os.popen(cmd_path+ ' show interfaces ethernet eth4 brief')
data = cmd_res.read()
cmd_res.close()

# Edgeos show interface command returns
# eth4        xxx.xxx.xxx.xxx
p = re.compile('eth4(\s*)(\d*).(\d*).(\d*).(\d*)')
m = p.search(data)

#m.groups()[0] is white space
if (m and len(m.groups()) == 5):
        current_ip = (m.groups()[1], m.groups()[2], m.groups()[3], m.groups()[4])
        try:
                last_ip = pickle.load(open('/home/user/myip/lastip', "rb" ))
        except IOError:
                last_ip = (1,2,3,4)

        if current_ip != last_ip:
                pickle.dump(current_ip,open('/home/user/myip/lastip', "wb" ))
                data ='<html><head><title>My IP</title></head><b>My IP:\
%d//%d//%d//%d</b></font></p></body></html>\
'%(int(m.groups()[1]),int(m.groups()[2]),int(m.groups()[3]),int(m.groups()[4]))
                output = StringIO.StringIO(data)
                ftp = ftplib.FTP('ftp.server.org', 'username','password')
                ftp.cwd('pub')
                ftp.storlines('STOR index.html', output)
                ftp.close()
        else:
                touch('/home/user/myip/lastip')

Obtaining the external WAN IP address from a Netgear WNR2000v5

Earlier I used a DNS service in order to get the IP address of my internet connection. I used some free ones, and they worked very well. Until they didn't work.

Then I used an external server, like duckduckgo.com, utilizing the computer, with python, already running in my house. Something like:

adr = "https://duckduckgo.com/?q=what+is+my+ip&ia=answer"
req = urllib2.Request(adr)
res = urllib2.urlopen(req)
data = res.read()
res.close()
...
p = re.compile('\"Answer\":"Your IP address is (\d*).(\d*).(\d*).(\d*) in')
m = p.search(data)
...
current_ip = (m.groups()[0], m.groups()[1], m.groups()[2], m.groups()[3])
...

This data were then uploaded to a know web page if it were different from the previous address.

And that worked great, until I occasionally started to use a VPN service on the machine running the script. Then duckduckgo.com returned the IP address of my VPN, which would not forward my ssh logins to my home.


So I checked my router, Netgear WNR2000v5, and it returned the IP address as expected. But only from the page "RST_conn_status.htm". It would also return "Access denied" for the first login attempt if someone had logged in to the router for another machine. And it required a username/password.

The script then became:

username='admin'
password='password'
adr = 'http://10.0.0.1/RST_conn_status.htm'
try:  #if someone else logged in to the router we get access denied the first time
 req = urllib2.Request(adr)
 base64string = base64.encodestring('%s:%s'%(username, password)).replace('\n', '')
 req.add_header("Authorization", "Basic %s" % base64string)   
 res = urllib2.urlopen(req)
except:
 time.sleep(1)

req = urllib2.Request(adr)
base64string = base64.encodestring('%s:%s' % (username, password)).replace('\n', '')
req.add_header("Authorization", "Basic %s" % base64string)   
res = urllib2.urlopen(req)
time.sleep(1)
data = res.read()
res.close()
...
p = re.compile('var info_get_wanip=\"(\d*).(\d*).(\d*).(\d*)\";')
m = p.search(data)
...
current_ip = (m.groups()[0], m.groups()[1], m.groups()[2], m.groups()[3])
...