Or, I think you could skip that if you setup the two, "actual" servers
to NAT all responses appropriate to DNS/DHCP ports, so everything always
looks like it's responding from the .250 address, regardless of whether
the .251 or .252 server actually sent the response.
I could be wrong.
On 12/22/2011 11:44 AM, Jan Seiffert wrote:
2011/12/22 Markus Schöpflin<markus.schoepf...@comsoft.aero>:
Thank you for your idea. This really seems OK for our needs. If I understand
things correctly, I would have to do that on all four LANs the current Dnsmasq
is serving. Just one small additional question:
Am 22.12.2011 15:13, schrieb Michael Rack:
Very easy.
You need at least one virtual ip-address for your DNS- and DHCP-Server.
So lets say you have a Class-C Network 10.0.0.0/24
* Primary DNS / DHCP 10.0.0.251
* Secondary DNS / DHCP 10.0.0.252
Now, you add a virtual IP to your primary DNS - lets say
* Virtual-IP 10.0.0.250
From Secondary you create a Bash-Script that do the following:
* Check the Server-Status by ping the virtual ip-address
* when the ping has failed:
* add the virtual ip-address to your network-configuration
Wouldn't it make sense to send an unsolicited ARP packet to update the ARP
caches of neighbours after the IP address has moved?
Yes.
I was about to write the same tip.
Sometimes ARP-Tables can have a quite long timeout, so the "failover"
would be stuck.
Maybe something along the lines of
arping -c 1 -A -s 10.0.0.250 $BROADCAST_ADDR
[snip]
Thank you,
Markus
Greetings
Jan
