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Posts: 243
Joined: Fri Feb 11, 2011 1:11 pm


Fri Feb 17, 2012 4:24 am


I'm using the dyndns script from the wiki, but it ain't perfect. It stops working after some time.
You see different log entries when it fails, you only see this in the logs:

12:09:26 script,info UpdateDynDNS: password = mypassw
12:09:26 script,info UpdateDynDNS: hostname =
12:10:26 script,info UpdateDynDNS: username = myuser
12:10:26 script,info UpdateDynDNS: password = mypassw
12:10:26 script,info UpdateDynDNS: hostname =
12:11:26 script,info UpdateDynDNS: username = myuser

The line:
12:28:27 info fetch: file "dyndns.checkip.html" created
doesn't appear in the logs anymore when it fails. This usually happens after a few weeks.
Any pointers?

I still don't understand why there's no dyndns client available in the firmware itself (one that writes to ramdisk and not to flash)
I hope this gets implemented one day, cause it's really annoying to loose connection with your devices when the dyndns script fails.

Kind regards
Posts: 45
Joined: Mon Oct 17, 2011 4:07 am

Re: Dyndns

Tue Feb 21, 2012 7:15 pm

I've used the same script on an RB750GL with no problems for at least a few months, non-stop.

From your logs, it looks like the fetch command might have hung/lost communication with the dyndns ip fetch site at some point? If that's the case, you can modify the script to check the IP of the WAN interface instead, and avoid having to use a fetch command at all. This also (minimally) reduces bandwidth. This is the relevant portion I've used:

:local currentIP
:local externalInterface "pppoe-out1"

# get the current IP address from the external interface
:set currentIP [/ip address get [find interface="$externalInterface"] address]
# Strip netmask
:for i from=( [:len $currentIP] - 1) to=0 step=-1 do={
:if ( [:pick $currentIP $i] = "/") do={
:set currentIP [:pick $currentIP 0 $i]


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