DNS A Record with 0.0.0.0 gets blocked by router

[simonwynn]

We have a system that uses DNS to communicate back to our systems, returning an A record with the contents 0.0.0.0 that indicates some state to us.

Any reason what this is being blocked by a router? Even with CBAC turned off?

An answer of 255.255.255.255 works fine... 0.0.0.0 gets blocked.

thanks,

Simon

[paolo bevilacqua]

How have you determined that router blocks that answer? And what is the router configuration.

[simonwynn]

Yes, it's the router - if we connect to the ISP / WAN side directly with a switch this query works. It's actually an issue with the T branch we used - changing to .25f main line efixed the issue.

Simon