Shulou(Shulou.com)06/02 Report--

Beans recently encountered a weird problem. After the company's iPhone/iPad is connected to WiFi, it can't download programs from App Store, but it can update programs that have already been downloaded, but there is no problem with itune AppleStore downloads on PC and Mac.

The wireless network setting of Douzi Company is relatively messy, the basic structure is that the client connects the switch and WLC through AP, and then different SSID also uses different authentication servers, some are WLC web page authentication, some are Windows Radius servers, some are Cisco ISE, and finally connect to the Internet through Palo Alto's firewall.

In short, Douzi spent a lot of time looking at firewall logs, grabbing packets, checking configuration files, testing and verifying server rules one by one, checked according to the entire route map, and then did not see any problems, and finally inadvertently found that the problem may be caused by the cache service of the OSX server.

Use the firewall log to confirm which IP accesses lcdn-registration.apple.com/lcdn/register, which is Cache server's registered server with Apple.

It is found that a large amount of traffic has been sent from 10.3.1.101. This IP is a Carper server of the company.

Log in, stop Cache Service, and find that the download immediately returns to normal!

Analysis: Cache Service will automatically register his public network IP with Apple's server, and then when other Apple devices on the same network try to update the software, the Apple server will redirect the request for this Cache Server. This can explain why the new software can not be downloaded, because there is no, but the old software has a record, so it can be updated.

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