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I'm setting up an ASA 5505 where the ISP provides a dynamic IP address (rarely changes.) I would like to start using some of the services provided by DynDNS such as Custom DNS.

I've come across some information regarding Cisco Routers and DynDNS, but nothing definitive on the ASA platform.

My question is whether I can configure the ASA5505 to update the IP address rather than install the DynDNS Updater software on a machine running on the LAN?


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If you're asking if you can get the ASA5505 to "register" with dyndns, the answer is no. Howeve, it appears that someone got a feature request added, though, under Cisco BugID CSCsl46782 . (If you don't have a Cisco service contract, you can't view the details). However, it looks like it has an extremely low priority and I wouldn't expect it to be added anytime soon.

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This is because businesses generally buy ASA devices, and they tend to have static IP services. – Tom O'Connor Dec 30 '11 at 9:02
You can view that ASA does not support the HTTP-based updates that DynDNS uses, in the following link from Cisco Support Community – Kalatzis Stefanos Jul 8 '12 at 11:18

I believe the SA500 series has the dyndns feature you are looking for. However that would be more money then installing the dyndns client on a system.

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Try to avoid statements like "I believe". Either you know and you can type it, or you don't and you shouldn't answer the question. – gparent Nov 14 '12 at 16:53

Dyn recommends using an update client on one of your computers, rather than your router.

In general, we have found the software clients in computers to be much more reliable compared to some router update clients. The reason for this is there are varying degrees of support for DynDNS in routers and other devices.

While these devices may claim to have DynDNS support, they sometimes are very buggy or not properly using our update API. This can cause issues such as abusive updates or maybe the update client not even being able to send us an update consistently. Abusive updates are the flooding our update servers with the same IP address every minute or so instead of only sending us an update when the IP address changes.

Software update clients are available for Windows, Mac OS X and Linux, so you should be able to squeeze one in just about anywhere.

In practice, having used Comcast Business for five years now without a static IP address, the IP address has changed only twice. The first time was immediately after an extended midday outage caused by a cable cut (~2 hours). The second was after moving to a new location. In each case I just updated my DynDNS records manually. (Your ISP may vary dramatically.)

I recommend you contact your ISP and get a static IPv4 address if this is a serious cause for concern. You should also consider obtaining an IPv6 allocation; these will be provided statically. A /56 should be sufficient for a small office environment.

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