Re: [Ddclient-support] DDClient Detecting a Second Gateway (Provider)???

[Ingo S. <isc...@as...>]

Hi Larry,

Larry Houston wrote on Sat, Jan 23, 2010 at 09:35:29PM -0500:

> Currently evaluating a "New" Provider, but had left both Gateways left 
> connected to our LAN's Switch.

You mean, you connect your Internet uplink directly to your LAN network
segment?  This remark is not related to ddclient, but if i understand
correctly what you are doing, it seems like a firewall is missing from
that network design.

> I had assumed that I could just modify Static Gateways on all Computers
> to switch between "Providers",

That doesn't look like a good approach, it may cause all sorts of issues.
For example, what about incoming connections?  They will continue to
arrive via both providers, and you may end up with asymmetric routing,
just to name one example.  Besides, what about your security policy,
and how are you planning to enforce it in that kind of setup?

> but to my surprise the DDclient (3.7.3 under Ubuntu 8.04) on occasion
> would use the Gateway of the "Old" Provider and consequently use that
> for its IP Address Determination and update my DynDNS Entry accordingly!!!
> Effectively "Flapping" between Providers, switching back to the "New"
> Provider 5 Minutes after updating the DynDNS Entry to reflect the "Old"
> Provider's IP Address...
> 
> Although I have now disconnected the Router for the "Old" Provider from 
> the LAN's Switch and expect the "Flapping" should stop, I am curious to 
> know by what mechanism the DDclient would have been able to "Discover" the 
> Second Router (Provider) without that being specified as a "Static" 
> Gateway???

That's hard to say.
Ddclient supports are large number of very different algorithms to
detect the IP address to publish, and you are telling us absolutely
nothing about your ddclient configuration.

If you hope for help, you would need to describe your network
topology in more detail and to show your ddclient confugration.

Yours,
  Ingo

-- 
Ingo Schwarze <isc...@as...> | Software Engineer | Framework Team
Astaro AG | www.astaro.com | 76227 Karlsruhe | Germany