Author Topic: dynamic dns  (Read 2210 times)


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dynamic dns
« on: October 31, 2008, 04:24:35 pm »
So, are the dynamic dns clients really only meant to be used when the core has a directly accessible public ip address on its external interface? This seems pretty limiting to me, as most installs are going to involve a cable modem or dsl router in front of the core which serves it a private ip.
I setup a dyndns account last night and initially set it up with the external ip it autodetected (207.something, iirc). Then I setup dyndns info in the dynamic dns section of the web admin. Now I see this morning that my dyndns address resolves to (the ip given to the core by my dsl router). Did i set something up wrong or is this service just completely useless for the majority of users?


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Re: dynamic dns
« Reply #1 on: October 31, 2008, 04:48:07 pm »
I'm not sure about the dynamic dns stuffin LMCE, but dynamic DNS works fine.  You need to know what you are doing to forward ports from your modem/router and use a static IP on the external side of your core.  The trick is grabbing the IP you show up as on the internet and using that to update your dynamic dns server.  I actually setup my core with dynamic dns before learning about the dynamic dns stuff in LMCE.  I'm also running dns on my core, using ddns only to point the nameserver for my domain to my dynamic IP.  Using as my dynamic dns server, as the name server for my domain name, and inadyn as the script to update dyndns, here is my cron.daily job.  It grabs my external IP from a website, checks to see if my external IP changed, updates my dns tables for things like mail and www, restarts my dns server, and updates my IP on dyndns:


# Update dyndns if IP changes

wget -O /tmp/realip
NEWIP=`awk -F: '{print $2}' /tmp/realip | awk -F\< '{print $1}'| sed s/' '//g`
OLDIP=`cat /tmp/oldip`
if [[ "$NEWIP" != "$OLDIP" ]]
   echo $NEWIP > /tmp/oldip
   sed s/NEWIPHERE/$NEWIP/g /etc/bind/ > /etc/bind/
   /etc/init.d/bind9 reload
   inadyn -u **MYLOGIN** -p **MYPASSWORD** --dyndns_system -a --iterations 1

Hopefully this is easier and is more automated within LMCE, but as I said I set this up before realizing LMCE had this as an option.


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Re: dynamic dns
« Reply #2 on: October 31, 2008, 09:12:35 pm »
I tried to utilize the DynDNS option in the LMCE web-admin too and then gave up on it. It was a while ago and I can't remember why I didn't continue to use it. I don't think it gave my internal IP but at the same time I don't think it updated my record either.

I configured the DynDNS page in my LinkSys router instead, and it works about 99%. I occasionally log into DynDNS just to ensure the IP is set correctly.

This is also interesting because I see ddclient running on my core when I do a "ps -aux" (it usually says sleeping x seconds). I don't know why it's running when in the admin panel the option is set to None. Seems like a waste of memory to me.