Update script for dynv6.com to set your IPv4 address and IPv6 prefix

dynv6.sh

#!/bin/sh -e
hostname=$1
device=$2
file=$HOME/.dynv6.addr6
[ -e $file ] && old=`cat $file`

if [ -z "$hostname" -o -z "$token" ]; then
  echo "Usage: token=<your-authentication-token> [netmask=64] $0 your-name.dynv6.net [device]"
  exit 1
fi

if [ -z "$netmask" ]; then
  netmask=128
fi

if [ -n "$device" ]; then
  device="dev $device"
fi
address=$(ip -6 addr list scope global $device | grep -v " fd" | sed -n 's/.*inet6 \([0-9a-f:]\+\).*/\1/p' | head -n 1)

if [ -e /usr/bin/curl ]; then
  bin="curl -fsS"
elif [ -e /usr/bin/wget ]; then
  bin="wget -O-"
else
  echo "neither curl nor wget found"
  exit 1
fi

if [ -z "$address" ]; then
  echo "no IPv6 address found"
  exit 1
fi

# address with netmask
current=$address/$netmask

if [ "$old" = "$current" ]; then
  echo "IPv6 address unchanged"
  exit
fi

# send addresses to dynv6
$bin "http://dynv6.com/api/update?hostname=$hostname&ipv6=$current&token=$token"
$bin "http://ipv4.dynv6.com/api/update?hostname=$hostname&ipv4=auto&token=$token"

# save current address
echo $current > $file

@uhardegger Thanks a lot for sharing your script! I've modified it a bit for my Synology router and added system log prints (to /var/log/messages). The modified version can be found here. The corresponding ddns_provider.conf file is uploaded here.

#!/bin/bash

#Configure
Hostname="example.dynv6.net"
IPVERSION="6" #IPV4=4, IPV6=6
UpdateURL="http://dynv6.com/api/update?hostname=$Hostname&ipv6=auto&token=YOUR_TOKEN"

RecordType=$([ "$IPVERSION" == 4 ] && echo "A" || echo "AAAA")

while true; do
 SavedIP=$(dig -$IPVERSION +short $RecordType $Hostname) #check IP which is stored on dynamic DNS
 ActualIP=$(dig -$IPVERSION +short $RecordType myip.opendns.com @resolver1.opendns.com) #get actual IP

 if [ "$SavedIP" != "$ActualIP" ] ; then
	wget -qO- $UpdateURL &> /dev/null
	if [[ $? -ge 0 ]]; then
	 SavedIP=$ActualIP
	fi
 fi

 sleep 5s #run every 5 seconds
done

Very simple and neat script that runs every 5 seconds in a loop. Has some advantages over the script above. Should work on most clients, includes a reliable way to get the IP and can be adapted to most dynamic DNS providers.

Configure hostname, record type and update URL, done.

For dynv6 you have to add your token in the URL. If you want to use IPV4, change IPVERSION to 4 and change url to ipv4 version of the URL. Then, simply copy it into a file like ddnsupdate.sh, chmod +x ddnsupdate.sh to make it executable and execute it from a startup script like rc.local: nohup /home/ddnsupdate.sh > /dev/null 2>&1&

There is example of systemd unit

[Unit]
After=miredo.service
[Service]
ExecStart=/usr/local/bin/ddnsupdate.sh
[Install]
WantedBy=default.target

Adapted findings and requirements from this thread into a n updated (and currently working) script. Depends on ns1.google.com ability to return a TXT record for o-o.myaddr.l.google.com. @Beaving did a similar thing with opendns but it did stop working as the "myip service" has been discontinued.

Script

#!/bin/bash

if [ -z "$DYNV6_HOSTNAME" -o -z "$DYNV6_TOKEN" -o -z "$DYNV6_PROTO" ]; then
  echo "Usage:"
  echo "DYNV6_HOSTNAME=hostname DYNV6_TOKEN=token DYNV6_PROTO=[4|6] $0"
  exit 1
fi;

record=$([ "$DYNV6_PROTO" == 4 ] && echo "A" || echo "AAAA")
resolved=$(dig +short $record $DYNV6_HOSTNAME )
actual=$(dig -$DYNV6_PROTO TXT +short o-o.myaddr.l.google.com @ns1.google.com | tr -d '"')

if [ "$resolved" != "$actual" ] ; then
  if [ "$DYNV6_PROTO" == "4" ] ; then
          curl "http://ipv4.dynv6.com/api/update?hostname=$DYNV6_HOSTNAME&ipv4=$actual&token=$DYNV6_TOKEN"
  fi

  if [ "$DYNV6_PROTO" == "6" ] ; then
          curl "http://ipv6.dynv6.com/api/update?hostname=$DYNV6_HOSTNAME&ipv6=$actual&token=$DYNV6_TOKEN"
  fi
fi

Example:

DYNV6_HOSTNAME=ramalamadingdong.dynv6.net DYNV6_TOKEN=muchSecureSoSecret DYNV6_PROTO=6 ./update_dns.sh

Please note that if you want to update v6 and v4 records, you will have to call the script twice.

like some other people before me realized: when the ipv6 has not changed, then the ipv4 address is not updated even if it has changed. This is due to 27, 32,40 where the script just exits.

I would open an issue for that if it were not only a gist but a full-fledged github repo. In the meantime - could i just suggest to actually put this script into a full-fledged github repo and to encourage the many people linking to their own versions in the comments here to make an effort and merge their diffs into the script so it actually becoms usable for noobs?

Many thanks for considering this!

I would open an issue for that if it were not only a gist but a full-fledged github repo. In the meantime - could i just suggest to actually put this script into a full-fledged github repo and to encourage the many people linking to their own versions in the comments here to make an effort and merge their diffs into the script so it actually becoms usable for noobs?

+1

Nice service!

I use the following systemd timer/service templates to enable the update on my hosts:

# /etc/systemd/system/dyndns@.service
[Unit]
Description=Update dynv6 DNS Entries

[Service]
Type=oneshot
EnvironmentFile=/etc/conf.d/dynv6
ExecStart=/usr/local/bin/dynv6.sh %I.dynv6.net

[Install]
WantedBy=multi-user.target

# /etc/systemd/system/dyndns@.timer
[Unit]
Description=Minutely dynv6 update

[Timer]
OnCalendar=minutely
Persistent=true

[Install]
WantedBy=timers.target

then enable/start:

sudo systemctl enable dyndns@MYHOSTNAME.timer
sudo systemctl start dyndns@MYHOSTNAME.timer

@corny

Since the 2019-10-31 update this does no longer work.

There is a new 'zone' parameter. I tried a few things like myhostname.dynv6.net, dynv6.net or empty, but each time I get:

HTTP/1.1 422 Unprocessable Entity
...

Error 1146: Table 'dynv6.hosts' doesn't exist

What should the zone parameter be set to? The api doc just says: 'Your DynV6 zone (mandatory) '

Use the zones ipv4.dynv6.com or ipv6.dynv6.com to enforce a specific IP protocol version.

Bit I also felt

I have the same problem. Since yesterday the update does not work anymore.
The documentation on dynv6.com is weird and confusing. I think what they want to say is, that you should use "ipv4.dynv6.com" as the url to query - not as zone parameter - to enforce ipv4 (ipv4.dynv6.com has only A records).
If you replace the foreign "hostname" parameter by "zone" (as the documentation says) it complains about a missing hostname. The API seems buggy to me...

Same issue here. Also https://dynv6.com/docs/apis currently is borked.

Just got into the dynv6 here and same problem.

Seems to be fixed now, without changing the url.

Sorry, we introduced a bug that has been fixed in the meanwhile.

I have a raspi behind a fritzbox acting as owncloud server. That worked well until Monday morning, when the IPv4 address got updated to
127.0.0.1. I changed the script instead of ipv4=auto in the api update command i use the current external IPv4 address. That fixes the problem.
Any idea why this suddenly happens? (no hardware or software changes/updates)

Same here

You can use address=$(wget -O- "https://api6.ipify.org")
(For ipv4 use https://api.ipify.org)

Or better place it below

if [ -e /usr/bin/curl ]; then
  bin="curl -fsS"
elif [ -e /usr/bin/wget ]; then
  bin="wget -O-"
else
  echo "neither curl nor wget found"
  exit 1
fi

To allow using curl or wget, depending on your setup.

if [ -e /usr/bin/curl ]; then
  bin="curl -fsS"
elif [ -e /usr/bin/wget ]; then
  bin="wget -O-"
else
  echo "neither curl nor wget found"
  exit 1
fi

address=$($bin "https://api6.ipify.org")

Because we don't want to use crontab to execute the script, we hope to execute the update script through the /etc/ppp/ipv6-up script of the system after establishing the pppoe session. But I found that after my router established pppoe session, the IPv6 address acquisition would be delayed, resulting in the update failure when $address was empty. Therefore, the base script is modified. When it is found that $address is empty, wait for 1 minute and then assign the value again, The loop ends after 30 times.

Note: crontab is not recommended for this script, which will increase the operating system load.
https://gist.github.com/hiifeng/0afc189bb79b3a6cc239d45af3ec6dbe

# When the address is empty, wait for 1 minute and then assign the value again. The loop ends after 30 times.
i=1
while [ $i -lt 30 ]
do
　address=$(ip -6 addr list scope global $device | grep -v " fd" | sed -n 's/.*inet6 \([0-9a-f:]\+\).*/\1/p' | head -n 1)
　if [ -z "$address" ]; then
　　sleep 1m
　　((i++))
　　else
　　　break
　fi
done

Here's a Python updater for IPv4 that updates to the IP of the PC the script is run on.
-Prerequisites
Python (duh)
requests the python module
pip install requests

Once done with the prerequisites, edit the script so the variables match your zone (hostname) and token.
Then run the script and the IPv4 address for your zone should update every 30 seconds!

I created two versions of the updater; an auto and a manual.

Manual Version:
https://gist.github.com/flid0/8784baff35ec061f00432a9db3525c20
Auto Version:
https://gist.github.com/flid0/91bd9a3e15b61a8fd5797c325b3451a0

DM me on Discord if you have any problems:
flido#0001

Only for IPV6 DDNS

filename: dynv6.sh
path:/usr/bin
chmod +x dynv6.sh

---

#!/bin/sh -e
GETIPV6="https://ip.ddnspod.com"
hostname="xxxxx.v6.rocks"
token="xxxxxxxxxxxxxxxxxxxxxxxxxx"

file=$HOME/.dynv6.addr6
[ -e $file ] && OldIP=cat $file
echo "[Old IP]:$OldIP"

NewIP=$(curl -6 -s -k $GETIPV6)
echo "[New IP]:$NewIP"

if [ "$OldIP" == "$NewIP" ];then
echo "IP IS SAME,SKIP UPDATE."
exit
fi

#send addresses to dynv6
curl "http://dynv6.com/api/update?hostname=$hostname&ipv6=$NewIP&token=$token"
#curl "http://ipv4.dynv6.com/api/update?hostname=$hostname&ipv4=auto&token=$token"

#save current address
echo $NewIP > $file

---

[root@C921 ~]# crontab -e
*/1 * * * * dynv6.sh &>/dev/null 2>&1

@andi34
the following script was out of work
address=$(wget -O- "https://api6.ipify.org")
"api64.ipify.org " always returns ipv4 address

@tolshao nope, works fine. Typo on your end? api64 vs api6?

I don't like caching the "old" IP in a file because if it was changed manually on dynv6.com or the update went wrong, the script doesn't notice.
So this variant works very well for me:

#!/bin/sh

HOSTNAME_DYNV6="****.dynv6.net"
TOKEN_DYNV6="****"

IP4ADDR=$(curl -s http://ipecho.net/plain)
IP6ADDR=`ip addr show eth0 | grep 'scope global dynamic' | grep -Po 'inet6 \K[0-9a-fA-F:]+'`

if [ "$IP4ADDR" = "" ]
then
        echo "Error: unable to determine IPv4 address" 1>&2
fi

if [ "$IP6ADDR" = "" ]
then
        echo "Error: unable to determine IPv6 address" 1>&2
fi

if [ "$IP4ADDR" != "" ]
then
	ping $HOSTNAME_DYNV6 -4 -c 1 > null # a little dirty - needed to update dns-cache
	IP4ADDR_DYNV6=$(dig $HOSTNAME_DYNV6 A +short)

	if [ "$IP4ADDR" != "$IP4ADDR_DYNV6" ]
	then
		echo "IPv4 adress has changed -> update ..."
		curl -s "https://ipv4.dynv6.com/api/update?hostname=$HOSTNAME_DYNV6&token=$TOKEN_DYNV6&ipv4=auto"
		echo "---"
	fi
fi

if [ "$IP6ADDR" != "" ]
then
        ping $HOSTNAME_DYNV6 -6 -c 1 > null # a little dirty - needed to update dns-cache
		IP6ADDR_DYNV6=$(dig $HOSTNAME_DYNV6 AAAA +short)

	if [ "$IP6ADDR" != "$IP6ADDR_DYNV6" ]
	then
		echo "IPv6 adress has changed -> update ..."
		curl -s "https://ipv6.dynv6.com/api/update?hostname=$HOSTNAME_DYNV6&token=$TOKEN_DYNV6&ipv6prefix=auto"
		echo "---"
	fi
fi

@tm-107 thanks for the script. While this did most of the work for me, I had to modify it to the following for it to work for my needs. For some reason auto was setting the IPV6 address to one that ended in :: and was missing the last three characters of my address. I made some small modifications to use the current address, including the netmask.

#!/bin/sh

HOSTNAME_DYNV6="****.dynv6.net"
TOKEN_DYNV6="****"
DEVICE_INTERFACE=eno1

IP4ADDR=$(curl -s http://ipecho.net/plain)
IP6ADDR_WITH_MASK=`ip -6 addr list scope global dynamic $DEVICE_INTERFACE | grep -Po 'inet6 \K[0-9a-fA-F:\/]+' | head -n1 | tr -d '\n'`
IP6ADDR=`echo $IP6ADDR_WITH_MASK | tr '/' '\n' | head -n1`

if [ "$IP4ADDR" = "" ]
then
        echo "Error: unable to determine IPv4 address" 1>&2
fi

if [ "$IP6ADDR" = "" ]
then
        echo "Error: unable to determine IPv6 address" 1>&2
fi

if [ "$IP4ADDR" != "" ]
then
	ping $HOSTNAME_DYNV6 -4 -c 1 > null # a little dirty - needed to update dns-cache
	IP4ADDR_DYNV6=$(dig $HOSTNAME_DYNV6 A +short)

	if [ "$IP4ADDR" != "$IP4ADDR_DYNV6" ]
	then
		echo "IPv4 adress has changed -> update ..."
		curl -s "https://ipv4.dynv6.com/api/update?hostname=$HOSTNAME_DYNV6&token=$TOKEN_DYNV6&ipv4=auto"
		echo "---"
	fi
fi

if [ "$IP6ADDR" != "" ]
then
        ping $HOSTNAME_DYNV6 -6 -c 1 > null # a little dirty - needed to update dns-cache
		IP6ADDR_DYNV6=$(dig $HOSTNAME_DYNV6 AAAA +short)

	if [ "$IP6ADDR" != "$IP6ADDR_DYNV6" ]
	then
		echo "IPv6 adress has changed -> update ..."
		curl -s "https://ipv6.dynv6.com/api/update?hostname=$HOSTNAME_DYNV6&token=$TOKEN_DYNV6&ipv6prefix=$IP6ADDR_WITH_MASK"
		echo "---"
	fi
fi

@tolshao and @andi34
curl https://api6.ipify.org will actually return an IPV4 address, but only if you have disabled IPV6. I imagine that was what happened above.

I made a simple batch file script for my Windows need, hope it can help someone too.

https://github.com/slyfunky/Pango/blob/main/DNS.bat

You should use https

Made my shell script like this. Think it's leightweight and easy to read

#!/bin/bash

# dynDNS with dynV6 & ipv6 done right

# Initial values

newIpV6=$(ip -6 addr show scope global | grep inet6 | sed -e 's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d')
oldIpV6='No data in cachefile'

# Change these parameters as you want to

logfile=~/dynv6.log
cachefile=~/.dynv6cache
token=<your-token>
zone=<your-zone>

if [[ -f $cachefile ]]; then
    oldIpV6=$(cat $cachefile)
fi

if [[ $newIpV6 != $oldIpV6 ]]; then
    echo "$(date): Updating the DNS. Output can be found in ${logfile}"
    echo "$(date): $(curl -k "https://dynv6.com/api/update?token=${token}&zone=${zone}&ipv6=${newIpV6}")" | tee -a $logfile
    echo $newIpV6 > $cachefile
else
    echo "$(date): IP did not Change. Skipping the update" | tee -a $logfile
fi

Use this as a cron job as often as you need and you should be good to go.

Made my shell script like this. Think it's leightweight and easy to read

#!/bin/bash

# dynDNS with dynV6 & ipv6 done right

# Initial values

newIpV6=$(ip -6 addr show scope global | grep inet6 | sed -e 's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d')
oldIpV6='No data in cachefile'

# Change these parameters as you want to

logfile=~/dynv6.log
cachefile=~/.dynv6cache
token=<your-token>
zone=<your-zone>

if [[ -f $cachefile ]]; then
    oldIpV6=$(cat $cachefile)
fi

if [[ $newIpV6 != $oldIpV6 ]]; then
    echo "$(date): Updating the DNS. Output can be found in ${logfile}"
    echo "$(date): $(curl -k "https://dynv6.com/api/update?token=${token}&zone=${zone}&ipv6=${newIpV6}")" | tee -a $logfile
    echo $newIpV6 > $cachefile
else
    echo "$(date): IP did not Change. Skipping the update" | tee -a $logfile
fi

Use this as a cron job as often as you need and you should be good to go.

I test it on my RPI4b,Which
ip -6 addr show scope global | grep inet6 | sed -e 's/^.inet6 ([^ ])/.*$/\1/;t;d'
will output two AAAA addr,and this script output error like this:
curl: (3) URL using bad/illegal format or missing URL
Sun 05 Feb 2023 09:45:55 AM CST:

can be fix by adding | head -n 1)

can be fix by adding | head -n 1)

Hi there, could you please tell a noob, at which position? I added it behind the URI and it didnt work
dynv6.sh: line 23: ` echo "$(date): $(curl -k "https://dynv6.com/api/update?token=${token}&zone=${zone}&ipv6=${newIpV6}")" | tee -a $logfile | head -n 1)'

Edit: I've read your comment with more care and figured it out. it should be like this:
newIpV6=$(ip -6 addr show scope global | grep inet6 | sed -e 's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d' | head -n 1)

This is my script (bash), free to use:

#!/bin/bash

bin="curl -fsS"

fqdn=<your_domain>
token='<Your_token>'

ipv4=dig TXT +short o-o.myaddr.l.google.com @ns1.google.com | cut -f2 -d'"'
ipv6=dig -6 TXT +short o-o.myaddr.l.google.com @ns1.google.com | cut -f2 -d'"'

echo "My Ipv6: "$ipv6
echo ""

if [[ $ipv6 =~ ^([0-9a-fA-F]{0,4}:){1,7}[0-9a-fA-F]{0,4}$ ]]
then
echo "Updating $fqdn (ipv6)..."
$bin "http://dynv6.com/api/update?hostname=$fqdn&ipv6=$ipv6&token=$token"
echo ""
else
echo "Invalid IPv6 address"
fi

echo "My IPv4: "$ipv4
echo ""

if [[ $ipv4 =~ ^[0-9]+.[0-9]+.[0-9]+.[0-9]+$ ]]
then
echo "Updating $fqdn (ipv4)..."
$bin "http://dynv6.com/api/update?hostname=$fqdn&token=$token&ipv4=$ipv4"
else
echo "Invalid IPv4 address"
fi

echo "End of DNS records update!"

exit 0
`

`