![]() ![]() Internet connection pre-flight checks have inherent race conditions, give false positives and false negatives, time-of-check to time-of-use problem.Knowing in advance how Wi-Fi will perform until you try is impossible. ![]() The reasons for these statements are next: Pre-flight checks have inherited race conditions.įrom Networking Best Practices, at 33:00:ĭon’t check the Reachability object to determine whether something is available. Pre-flight check is a very bad indicator of where your flow will end up on.įrom Advances in Networking, Part 2, at 56:00 From Advances in Networking, Part 1, at 50:00: We can hear similar pieces of advice in multiple WWDC sessions. The SCNetworkReachability API is not intended for use as a preflight mechanism for determining network connectivity. In its documentation, Apple says that we should not check Internet connection before firing an HTTP request. Checking Connectivity Before Firing a Request In this article, let’s discuss why this solution is less than optimal, and lay out best practices of working with the Internet connection recommended by Apple. The most popular answers on how to detect network connectivity status on iOS suggest using SCNetworkReachability. Attaching constraints to network operations, e.g., disabling large file download via cellular.Disabling or enabling app features based on network connectivity status.Checking connectivity before firing an HTTP request.Typically, it appears in three scenarios: A common network-related task is Internet connectivity detection. Now, go through the capture and try to ascertain what device may be at fault, this will also tell you the mac/user involved and you can go check in access tracker what happened at the CPPM side.Networking is an integral part of most iOS applications. When there is a timeout what does the access tracker say, is it rejecting/ignoring an auth attempt.Īs you note it's happening all of the time, perhaps you can setup a packet capture for udp 1812/1813 and let it run for a while until you know there is at least one timeout according to the controller CLI. I presume that your CPPM is in a healthy state and not under and duress (what does the CPPM monitoring say?). Server Acct Rq Raw Rq PAP Rq CHAP Rq MSCHAP Rq MSCHAPv2 Rq Mismatch Rsp Bad Auth Acc Rej Acct Rsp Chal Ukn Rsp Tmout AvgRspTm Tot Rq Tot Rsp Rd Err Outstanding Auths Outstanding Requests Acc-RTTS Rq Acc-RTTS Rsp ExpAuthTm Uptime SEQĭoes_not_exist 0 0 1 0 0 0 0 0 0 0 0 0 0 4 0 1 0 0 0 0 0 0 5022 0:0:1 255/254Īs to why your server is timing out - that could be any number of things. You can see 4 messages 5 seconds apart, corresponds to 3 rexmt at 5 seconds (default of a new radius server) show aaa authentication-server radius does_not_existĬheck stats (7008-core) #show aaa authentication-server radius statistics Resulting log (7008-core) #show log errorlog 20 ![]() Now test it (7008-core) #aaa test-server pap does_not_exist no_such_user aaaaaaa ![]() (7008-core) ^ (RADIUS Server "does_not_exist") #key blah (7008-core) (config) #aaa authentication-server radius does_not_exist Timeout means the server did not respond, e.g. ![]()
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