Hi I'm looking to add more robustness into my proxy architecture and noticed in the home_server_pool there is the option for "fallback = virtualrealm" so if all home servers fail then a last resort home_server is used with some config locally to always accept / reject customers based on the realm they are coming from. I'm not using the status_check as some of the downstream clients don't support status-server, but I will look into that to see if it makes a difference. However for this situation I would expect if you are using or not using Status server checks shouldn't have any impact on how the fallback server works. In the proxy.conf I have configured: home_server ProxyDest { type = auth+acct ipaddr = 192.168.1.113 port = 1812 secret = password response_window = 1 require_message_authenticator = no zombie_period = 5 revive_interval = 10 status_check = none #status_check = status-server # username = "test_user_please_reject_me" # password = "this is really secret" check_interval = 10 num_answers_to_alive = 3 max_outstanding = 65536 } home_server cacheuser { virtual_server = cacheuser } # Main server pool # home_server_pool ProxyDestPool { type = fail-over home_server = ProxyDest # home_server = cacheuser fallback = cacheuser } Then in my virtual server I have configured: server cacheuser { authorize { accept } So when the Destination server is up life is good. (0) Proxying request to home server 192.168.1.113 port 1812 timeout 1.000000 (0) Sent Access-Request Id 26 from 0.0.0.0:58512 to 192.168.1.113:1812 length 337 ... Waking up in 0.3 seconds. (0) Marking home server 192.168.1.113 port 1812 alive (0) Clearing existing &reply: attributes (0) Received Access-Accept Id 26 from 192.168.1.113:1812 to 192.168.1.116:58512 length 55 But if the server is down the first request I get a reject as expected due to the home server being down. (2) Proxying request to home server 192.168.1.113 port 1812 timeout 1.000000 (2) Sent Access-Request Id 17 from 0.0.0.0:47755 to 192.168.1.113:1812 length 337 ... Waking up in 0.3 seconds. (2) Expecting proxy response no later than 0.669753 seconds from now Waking up in 0.4 seconds. (2) No proxy response, giving up on request and marking it done Marking home server 192.168.1.113 port 1812 as zombie (it has not responded in 1.000000 seconds). (2) ERROR: Failing proxied request for user "peter", due to lack of any response from home server 192.168.1.113 port 1812 (2) Clearing existing &reply: attributes But the second and subsequent request I would expect to get proxied to the local fallback virtual server as the home_server has been marked as zombie. But that never seems to happen. It keeps on rejecting the requests and fallback never seems to be used. If I configure a second home server in the pool. home_server_pool ProxyDestPool { type = fail-over home_server = ProxyDest home_server = cacheuser fallback = cacheuser } Then the second server is failed over to when the first fails. Which is all good if I wanted to use the type fail-over, but if I wanted to use load-balance then I can't have my fallback server as a home server otherwise a percentage of requests will always be local which isn't ideal. The other interesting thing with the failover is I set the check_interval to 10 seconds, or 30 seconds. But it only seems that the first client is re-checked after 60 seconds and assumed to be back up. Waking up in 0.2 seconds. Marking home server 192.168.1.113 port 1812 alive again... we have no idea if it really is alive or not. Waking up in 1.0 seconds. I would have thought that zombie_period = 5 revive_interval = 10 check_interval = 10 Would mean that the client would be re-checked in 10 seconds. Am I mis-understanding how fallback is supposed to work? Cheers Peter