[kwlug-disc] Getting external IP

[bob+kwlug at softscape.ca]

Ronald,

Thanks for sharing that. 

Thankfully, I don't need this, but I do remember looking for ways to do this and took some notes. 

These are the ones I found:

    curl http://checkip.dyndns.com/
    google search "my IP address"
    curl ifconfig.me
    host myip.opendns.com resolver1.opendns.com
    dig TXT +short o-o.myaddr.l.google.com @ns1.google.com
    curl ifconfig.me
    curl icanhazip.com
    curl ipecho.net/plain
    curl ifconfig.co

Not sure the state of any of those, but if anyone needs options, go nuts.

BB




> -----Original Message-----
> From: kwlug-disc [mailto:kwlug-disc-bounces at kwlug.org] On Behalf Of Ronald
> Barnes
> Sent: Monday, January 29, 2018 12:51 PM
> To: kwlug-disc at kwlug.org
> Subject: Re: [kwlug-disc] Getting external IP
> 
> bob+kwlug at softscape.ca wrote on 2018-01-29 08:12 AM:
> 
> > Did you modify named itself with your custom code? What's actually
> > listening on port 53 on your server here?!?
> 
> Wrote from scratch in Python as a learning project for Python and a
> handy utility for getting external IPs since I didn't know about the
> other choices at the time.
> 
> So, in Python:
> 
> > IP_ADDR = '0.0.0.0'
> > IP_PORT = 53
> 
> > try:
> >         s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
> >         s.bind(( IP_ADDR, IP_PORT))
> >         debugMessage(format("Bound to IP :: port --> %s :: %s " \
> >                 % (IP_ADDR, IP_PORT) ), \
> >                 verb=0);
> >         print >> logFH, time.strftime('%Y-%m-%d %H:%M:%S'), \
> >                 "STARTED LISTENING"
> > except:
> >         print "\nERROR binding to socket at %s :: %d:\n\t%s" \
> >                 % (IP_ADDR, IP_PORT, exc_info()[1] )
> >         raise SystemExit
> 
> 
> Note that this is a non-recursive DNS server, so won't resolve, say,
> google.ca and can't become part of a DNS reflection attack:
> 
> > $ dig google.ca @kwvoip.ca
> >
> > ; <<>> DiG 9.10.3-P4-Ubuntu <<>> google.ca @kwvoip.ca
> > ;; global options: +cmd
> > ;; Got answer:
> > ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 22233
> 
> "SERVFAIL" should cause client to query its second DNS server.
> 
> 
> 
> It does, however, return NXDOMAIN for a small list of sites I'd rather
> not have access too (*cough* advertisers *cough*).
> 
> i.e.:
> 
> > $ dig doubleclick.net @kwvoip.ca
> >
> > ; <<>> DiG 9.10.3-P4-Ubuntu <<>> doubleclick.net @kwvoip.ca
> > ;; global options: +cmd
> > ;; Got answer:
> > ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 17598
> 
> NXDOMAIN indicates "I'm certain this is bad, no need to look further".
> 
> 
> This should make it a handy primary DNS server entry at one's router to
> give a bit of an ad-free experience for all connected devices,
> regardless of whether they're running blockers on each device.
> 
> 
> Cheers,
> 
> r b
> 
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