Andy Bennett wrote: > In failure cases existing clients will wobble for a bit until their > cache expires and then the connections will have to be reestablished. > I wish it were that straightforward. After performing several switchovers where DNS A records were repointed, many clients (days later) continue trying to access the old servers. TTL on the DNS records are set appropriately short, this is simply a case of mail clients inappropriately caching DNS results. The fix for this is to restart the client, sometimes requiring a reboot of the machine to accomplish. Additionally, several clients perform a capability check when they initially connect to a server, but don't re-verify this until restarted. If the two servers are different, it can cause problems. This typically involves supported/preferred authentication mechanisms between systems - not typically a problem in a cluster, but could be a problem in a fail over scenario to a different system. --Blake ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
