Juniper SRX – DynDNS

As it stands Juniper SRX (version 11.1R1.10) only provides support for DynDNS (DDNS) via the use of an automation script.

Configuration

This script can be downloaded here. Once you have downloaded the script transfer it to the SRX directory /var/db/scripts/event/.

Finally configure your SRX via the following commands :

set system services apply-macro dyndns-client1 hostname XXX.dyndns.org
set system services apply-macro dyndns-client1 password <PASSWORD>
set system services apply-macro dyndns-client1 type dyndns
set system services apply-macro dyndns-client1 username <USERNAME>

set event-options policy dyn-dns-updater events SYSTEM
set event-options policy dyn-dns-updater attributes-match SYSTEM.message matches “EVENT Add”
set event-options policy dyn-dns-updater then event-script dyn-dns-update.xslt

set event-options event-script file dyn-dns-update.xslt

Troubleshooting

  1. Ensure that you do not have any filters denying traffic (DNS or HTTP) that is required for DynDNS updates.
  2. Enable full logging and inspect the logs for issues. Use the command ‘set system syslog file dyn-debug any any‘.

Additional

I found that when using IPv6 and PPPoE additional entries can be generated that contain the string “EVENT Add” which incorrectly triggers the DynDNS update script. Updating DynDNS with IP addresses that have not changed is deemed abuse and as a result you can be temporarily denied/banned from using DynDNS. To resolve this the following configuration change is required.

– set event-options policy dyn-dns-updater attributes-match SYSTEM.message matches “EVENT Add”
+ set event-options policy dyn-dns-updater attributes-match SYSTEM.message matches “EVENT Add pp0.0”

Rick Donato

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