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 -- Remember to eat a healthy breakfast, for tonight we dine in hell!
