Exchange 2013 CU7
If you are getting this error on the CAS servers
[Eas] The number of outstanding requests for guard TargetBackend(“servername”) has exceeded the max limit 150. Current request will be rejected.
And this error on the Microsoft Web Application Proxy
The HTTP response from the back end server was not received within the expected interval. Expected interval: 300 seconds.
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Details:
Transaction ID: {f4be1653-43e9-0000-02d0-bef4e943d001}
Session ID: {f4be1653-43e9-0000-02d0-bef4e943d001}
Published Application Name: Exchange Microsoft-Server-ActiveSync
Published Application ID: 9ad23d25-1d98-7a66-3671-6cd7aabcab29
Published Application External URL: https://mailserver.address.com/Microsoft-Server-ActiveSync/
Published Backend URL: https://mailserver.address.com/Microsoft-Server-ActiveSync/
User: <Unknown>
User-Agent: Apple-iPhone5C2/1104.257
Device ID: <Not Applicable>
Token State: NotFound
Cookie State: NotFound
Client Request URL: https://mailserver.address.com/Microsoft-Server-ActiveSync?User=user@address.com&DeviceId=ApplF2LL1VVXDTWF&DeviceType=iPhone&Cmd=Ping
Backend Request URL: https://mailserver.address.com/Microsoft-Server-ActiveSync?User=user@address.com&DeviceId=ApplF2LL1VVXDTWF&DeviceType=iPhone&Cmd=Ping
Preauthentication Flow: PassThrough
Backend Server Authentication Mode: PassThrough
State Machine State: BEBodyWriting
Response Code to Client: <Not Applicable>
Response Message to Client: <Not Applicable>
Client Certificate Issuer: <Not Found>
Try
Reference here
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On all CAS servers:
In \Exchange Server\V15\FrontEnd\HttpProxy\sync\web.config, add this key in the <appSettings> node.
<add key=”HttpProxy.ConcurrencyGuards.TargetBackendLimit” value=”5000″ />
In \Exchange Server\V15\FrontEnd\HttpProxy\rpc\web.config, add this key in the <appSettings> node.
<add key=”HttpProxy.ConcurrencyGuards.TargetBackendLimit” value=”5000″ />
After this change recycle the MSExchangeSyncAppPool and MSExchangeRPCProxyAppPool in IIS manager.
After this, we stopped getting Event ID 2002, and all Connection_Dropped_Event_List_Full stopped appearing in Httperror logs.
Awesome! Any idea on the location of the config files to change on Exchange 2010 with this issue?
Sorry, I don’t know where the files are for 2010 but if I find out I will update this post. I’m assuming in not in the same location but the V14 directory?
Edd
Hi Edd
We installed CU11 for Exchange 2013 yesterday (we are Migrating from Exchange 2007 and have mapi/http issues that are resolved in CU11).
We ran CU9 untill the upgrade and did the changes to the web.config files as you described to get rid of the “[Eas] The number of outstanding requests for guard TargetBackend(“servername”) has exceeded the max limit 150. Current request will be rejected.”
After we installed CU11 (and the web.config files of course were updated) we applied the changes again. This caused the NetScaler cluster to mark Active Sync and rpc as down on all our eight servers and no one could synchronize their mobile devices with Active Sync.
As soon as we removed the “” line from the web.config files everything started working again.
We are currently working with MS to resolve this issue as the “old” warning is back due to the fact that we cannot apply the changes to the web.config files.
Hope this helps if you are going to apply CU11
Hi Thomas,
Did you already have a solution for this issue from MS or Citrix?
We currently have Exchange 2013 CU10 and recently completed the migration from Exchange 2007. We are also this event (2002) on one of our Exchange CAS servers. But, after making the changes referenced above and bouncing the app pools, users were not able to connect to Exchange. Deleting the lines from the web.config files and bouncing the app pools again got users connected again but the 2002 events returned.