Updating Dynamic Dns only if changed?

[nitro001]

Hello,
I am using a AC66R router with the latest Merlin 387.55 firmware.
Is it possible to only send updates to a DDNS service if the IP of the WAN has changed?
I am using DNS-O-Matic and since I have moved every once in a while my cable modem decided to go flaky and looses its connection and has to renegotiate the connection. Sometimes this takes a while, but it works, and I believe it is an issue with Time Warner on their end with signal strength; however, every time this happens, the router sees the loss of the IP and the fact it gets a new one; but then sends the request right on to DNS-O-Matic, where I receive a nice email back:

Below is the most recent response from your DNSexit service registered at DNS-O-Matic.


DNSexit response for '****.linkpc.net':
--------------------
HTTP/1.1 200 OK
4=IP not changed. To save our system resources, please don't post updates unless the IP got changed.
--------------------

- The DNS-O-Matic Team


so DNS-O-Matic knows that the IP had not changed, and this is the only way as of now I know my modem has rebooted itself when I am away; but I don't want to get removed from DNS-O-Matic or any other DDNS service for updating or reporting too frequently.

What I am getting at, is there a way that the router to remember the IP from the last request and only send if it had changed from the last one? It seems Time Warner is re-assigning me the same IP address over and over.

Thanks.

 

[Martineau]

Hello,
I am using a AC66R router with the latest Merlin 387.55 firmware.
Is it possible to only send updates to a DDNS service if the IP of the WAN has changed?
I am using DNS-O-Matic and since I have moved every once in a while my cable modem decided to go flaky and looses its connection and has to renegotiate the connection. Sometimes this takes a while, but it works, and I believe it is an issue with Time Warner on their end with signal strength; however, every time this happens, the router sees the loss of the IP and the fact it gets a new one; but then sends the request right on to DNS-O-Matic, where I receive a nice email back:

Below is the most recent response from your DNSexit service registered at DNS-O-Matic.


DNSexit response for '****.linkpc.net':
--------------------
HTTP/1.1 200 OK
4=IP not changed. To save our system resources, please don't post updates unless the IP got changed.
--------------------

- The DNS-O-Matic Team


so DNS-O-Matic knows that the IP had not changed, and this is the only way as of now I know my modem has rebooted itself when I am away; but I don't want to get removed from DNS-O-Matic or any other DDNS service for updating or reporting too frequently.

What I am getting at, is there a way that the router to remember the IP from the last request and only send if it had changed from the last one? It seems Time Warner is re-assigning me the same IP address over and over.

Thanks.

http://www.snbforums.com/threads/ddns-duckdns-org.16649/#post-169499

 

[nitro001]

But isn't that for a custom DDNS entry and not the Built-in DNS-O-MATIC entry?
Using that I would have to set the Custom entry, create the script it is asking for, then find out what the calling URL to DNS-O-MATIC is with the correct URL items, right?

 

[Martineau]

But isn't that for a custom DDNS entry and not the Built-in DNS-O-MATIC entry?
Using that I would have to set the Custom entry, create the script it is asking for, then find out what the calling URL to DNS-O-MATIC is with the correct URL items, right?

https://github.com/RMerl/asuswrt-merlin/wiki/Custom-DDNS

 

[nitro001]

I think I finally got it:
#!/bin/sh
# Update the following variables:
USERNAME=dnsomatic_username
PASSWORD=dnsomatic_password
HOSTNAME=all.dnsomatic.com

MYROUTER=$(nvram get computer_name)
MY_WANIPADDR=$(nvram get wan0_ipaddr)
ROUTERFILE=/tmp/DDNS_IPADDR.txt
TEMPFILE=/tmp/DDNS_IPADDR.tmp
touch $ROUTERFILE
MY_WANIPADDRX=$(cat $ROUTERFILE)

logger -s -t "($(basename $0))" $$ Previous WAN IP $MY_WANIPADDRX
logger -s -t "($(basename $0))" $$ Current WAN IP $MY_WANIPADDR
echo "" >$TEMPFILE

# Check if I/P address has changed
if [ "$MY_WANIPADDR" = "$MY_WANIPADDRX" ]; then
echo "My "$ISP" t'Tinterweb IP address is: "$MY_WANIPADDR >>$TEMPFILE
echo "" >>$TEMPFILE
logger -s -t "($(basename $0))" $$ WAN IP unchanged
/sbin/ddns_custom_updated 1
else
echo "I just got connected t'Tinterweb." >>$TEMPFILE
echo "" >>$TEMPFILE
echo "My new "$ISP" IP address is: >"$MY_WANIPADDR"< was >"$MY_WANIPADDRX"<" >>$TEMPFILE
echo "" >>$TEMPFILE
logger -s -t "($(basename $0))" $$ WAN IP changed!!!

# Should be no need to modify anything beyond this point
/usr/sbin/curl -k --silent "https://$USERNAME:$PASSWORD@updates...ME&wildcard=NOCHG&mx=NOCHG&backmx=NOCHG&myip=" > /dev/null
echo "https://$USERNAME:$PASSWORD@updates...ME&wildcard=NOCHG&mx=NOCHG&backmx=NOCHG&myip=" >> $TEMPFILE
if [ $? -eq 0 ]; then
/sbin/ddns_custom_updated 1
else
/sbin/ddns_custom_updated 0
fi

# Save the current WAN I/P address
echo "$MY_WANIPADDR" > $ROUTERFILE
fi