KingDezigns — DDNS Updater Summary

What was built

A self-contained Bash script that keeps all KingDezigns DreamHost A records synchronized with the current home WAN IP. It runs every 15 minutes via OMV Scheduled Tasks. It only calls the DreamHost API when the IP actually changes (or during a nightly sanity check), so there is zero risk of being banned for spamming.

20 A records managed 4 domains Max 2 API calls per event HTML email notifications Every 15 min via cron Daily sanity check 00:00–00:14

Logic flow map

⏱ Script runs (every 15 min via OMV cron)

↓

🌐 Get current WAN IP from api.ipify.org / ifconfig.me / icanhazip.com

↓

📄 Read cached previous IP from /var/log/ddns/last_wan_ip.txt

↓

🕛 Is the time between 00:00 and 00:14? (daily sanity-check window)

↓

IP changed OR daily window

▶ Query DreamHost — check each A record

📡 Call dns-remove_record + dns-add_record for each mismatched record

⏳ Wait 3–5 minutes (random)

🔍 Re-query DreamHost — verify each record

Still wrong

🔁 Attempt 2 of 2 — update remaining records

⏳ Wait 3–5 min · Re-verify

Still failing

✗ STOP (max attempts reached)

📧 Email: partial failure + manual fix instructions + WAN IP

Now correct

✓ Mark success

📧 Email: all records updated

All correct

✓ All records verified

📧 Email: success — all records updated

💾 Write new WAN IP to cache file

IP unchanged + not daily window

💾 Overwrite cache with same IP (refreshes timestamp)

🔇 Exit silently — no API calls, no email

⚠ DreamHost API — how updates work

DreamHost has no "update" DNS command. To change an A record you must remove the old value then add the new one. The script always fetches the live DreamHost value immediately before each remove/add pair so it never tries to remove a value that isn't there.

Domains & records managed

Record (DreamHost "record" field)	Zone / Domain	Type
`albranch.org`	albranch.org	A (root / @)
`www.albranch.org`	albranch.org	A
`indigorhayne.com`	indigorhayne.com	A (root / @)
`www.indigorhayne.com`	indigorhayne.com	A
`rufusking.com`	rufusking.com	A (root / @)
`www.rufusking.com`	rufusking.com	A
`kingdezigns.com`	kingdezigns.com	A (root / @)
`www.kingdezigns.com`	kingdezigns.com	A
`*.web.kingdezigns.com`	kingdezigns.com	A (wildcard)
`cloud.kingdezigns.com`	kingdezigns.com	A
`files08.kingdezigns.com`	kingdezigns.com	A
`files16.kingdezigns.com`	kingdezigns.com	A
`has.kingdezigns.com`	kingdezigns.com	A
`nginx.kingdezigns.com`	kingdezigns.com	A
`omv08.kingdezigns.com`	kingdezigns.com	A
`omv16.kingdezigns.com`	kingdezigns.com	A
`pihole.kingdezigns.com`	kingdezigns.com	A
`plex.kingdezigns.com`	kingdezigns.com	A
`vault.kingdezigns.com`	kingdezigns.com	A
`webmin.kingdezigns.com`	kingdezigns.com	A

Deployment — step by step

1 Install dependencies

sudo apt-get update
sudo apt-get install -y curl python3 mailutils

curl fetches WAN IP and calls the DreamHost API. python3 parses the JSON responses. mailutils provides the mail command for sending HTML notifications.

2 Copy the script to its permanent location

sudo cp ddns_update.sh /usr/local/sbin/ddns_update.sh

This puts it in a root-only system bin directory alongside other admin utilities.

3 Set ownership and permissions

sudo chown root:root /usr/local/sbin/ddns_update.sh
sudo chmod 700 /usr/local/sbin/ddns_update.sh

The script reads/writes to /var/log/ddns/ and calls sendmail — it must run as root. Mode 700 prevents other users from reading the embedded API key.

4 Create the log directory

sudo mkdir -p /var/log/ddns
sudo chmod 700 /var/log/ddns

The script will create this automatically on first run, but creating it manually with 700 ensures no other user can read the cached IP or logs before then.

5 Test a manual run

sudo /usr/local/sbin/ddns_update.sh

Run once by hand to verify API connectivity, confirm all 20 records are found, and check that the email arrives at rufus.king@kingdezigns.com. Watch the output — it prints everything it does.

On the very first run there is no cached IP, so it will treat every record as new and perform a full update cycle.

6 Verify the log file after test run

sudo cat /var/log/ddns/ddns_run.log

You should see the WAN IP detected, DreamHost responses for each record, and "DDNS run complete" at the bottom.

7 Add OMV Scheduled Task

OMV → System → Scheduled Tasks → + (Add)

  Enabled:   ✓
  Minute:    */15
  Hour:      *
  Day:       *
  Month:     *
  Weekday:   *
  User:      root
  Command:   /usr/local/sbin/ddns_update.sh

This fires the script every 15 minutes around the clock. OMV uses standard cron under the hood — you can verify with sudo crontab -l after saving.

Script is now live and fully automated.

Script & files created

Script location

/usr/local/sbin/ddns_update.sh

IP cache (previous WAN IP)

/var/log/ddns/last_wan_ip.txt

Run log (last 5000 lines, auto-trimmed)

/var/log/ddns/ddns_run.log

Notification email

rufus.king@kingdezigns.com

Manual run command

sudo /usr/local/sbin/ddns_update.sh

Force a fresh update (clears cache)

sudo rm /var/log/ddns/last_wan_ip.txt && sudo /usr/local/sbin/ddns_update.sh

Watch the live log

sudo tail -f /var/log/ddns/ddns_run.log

Email notification behavior

Scenario	Email sent?	Subject line
IP unchanged, not daily window	No	Silent exit — no email
IP changed, all records updated successfully	Yes	[DDNS] ✅ All Records Updated — <new IP>
IP changed, some records failed after 2 attempts	Yes — action needed	[DDNS] ⚠️ PARTIAL FAILURE — Manual action needed — <new IP>
Daily sanity check (00:00–00:14), all records match	Yes	[DDNS] ✅ All Records Updated — <IP>
Daily sanity check, mismatch found & fixed	Yes	[DDNS] ✅ All Records Updated — <new IP>
WAN IP discovery fails (all 3 sources down)	No	Script aborts — will retry next 15-min run

All emails are sent as HTML using the KingDezigns branded template — same typography and color system as this document. They include a record-by-record results table and, on failure, a direct link to the DreamHost DNS panel with the correct IP pre-noted for manual entry.

Important notes & gotchas

Item	Detail
API key is embedded in the script	The script is chmod 700 / root only. Do not copy or share the file without scrubbing the key first.
DreamHost has no "update" API command	Every update is a remove + add pair. The script always reads the live DreamHost value first so it never removes the wrong IP.
Wildcard record `*.web.kingdezigns.com`	DreamHost supports wildcard A records via API. The script passes the literal string `*.web.kingdezigns.com` to `dns-list_records` and it will match correctly.
Mail must be configured on NAS16	Run `sudo apt-get install mailutils` and ensure your MTA (Postfix or ssmtp) is configured to relay outbound email. Test with: `echo "test" \| mail -s "test" rufus.king@kingdezigns.com`
First run behavior	On the very first run there is no cached IP. The script treats every record as needing an update and performs a full cycle. This is expected and correct.
Daily window fires once per day	The 00:00–00:14 window aligns with the every-15-min schedule — only one run per day falls in that window. No extra logic needed.
Log rotation	The run log auto-trims itself to 5000 lines on every execution. No logrotate config needed.