multi-homed bind

[Kevin Darcy]

Todd Hackett wrote:

> Howdy All!
>
> I have what seems to be a problem or feature.  But first:
>
> Bind on RH7.0    yes, yes, I know - will update soon.
> 3 NIC's, two live, one local - each on different networks.
>
> Unreliable DSL to the two live, with static ip's.
>
> The thought is if one of the DSL connections go down, it takes the DNS server with it, which would cause the other to take over and point to the proper IP for the same service: DNS,  MAIL, and HTTP.  This seems to work fine.
>
> Ok, lets see if I can pose this correctly.  One box, two live DNS server IP addresses; lets call them IP1 and IP2.  Bind listening on IP1 sends out ARP requests on the IP1 network, it also sends out ARP requests on IP2 WITHOUT changing the reverse (or IP, depending on how you look at it ). This is not correct, as it is putting invalid IP addresses on another network, (martain sources).  Shouldn't bind limit itself to only the IP network that it is listing on?
>
> Hope that made sense!

Sorry, it still doesn't make sense to me. What does ARP have to do with DNS? Also, the names that a nameserver serves have little or no relation to the addresses on which it is listening on. Are you expecting some sort of "automatic" address-translation logic? It just isn't there. If you want your DNS to answer differently depending on what network interface it is answering on, then you need to run multiple nameserver instances on the same box (BIND 8) or, even
better, use BIND 9's "view"s (assuming that the clients can be differentiated by their source addresses).

                                                                                            - Kevin