[horde] Proxy errors to downstream Horde server

Sun Jun 9 15:14:20 UTC 2013

Quoting Simon Wilson <simon at simonandkate.net>:

> My Horde box is reverse proxied by an Apache box - that box  
> consistently logs these errors about every one to two minutes:
>
> [Sun Jun 09 20:56:35 2013] [error] [client 59.167.157.243]  
> (70007)The timeout specified has expired: proxy: error reading  
> status line from remote server 192.168.1.230
> [Sun Jun 09 20:56:35 2013] [error] [client 59.167.157.243] proxy:  
> Error reading from remote server returned by  
> /Microsoft-Server-ActiveSync
>
> [Sun Jun 09 20:58:36 2013] [error] [client 59.167.157.243]  
> (70007)The timeout specified has expired: proxy: error reading  
> status line from remote server 192.168.1.230
> [Sun Jun 09 20:58:36 2013] [error] [client 59.167.157.243] proxy:  
> Error reading from remote server returned by  
> /Microsoft-Server-ActiveSync
>
> [Sun Jun 09 21:00:39 2013] [error] [client 59.167.157.243]  
> (70007)The timeout specified has expired: proxy: error reading  
> status line from remote server 192.168.1.230
> [Sun Jun 09 21:00:39 2013] [error] [client 59.167.157.243] proxy:  
> Error reading from remote server returned by  
> /Microsoft-Server-ActiveSync
>
> Everything seems to be working OK, and there are no issues logged at  
> the actual Horde server...
> The proxy's apache access log has entries like this recorded as  
> originating at 120 seconds before each error pair:
>
> 59.167.157.243 - - [09/Jun/2013:20:54:35 +1000] "POST  
> /Microsoft-Server-ActiveSync?Cmd=Ping&User=simon%40simonandkate.net&DeviceId=SEC10D1C297BE813&DeviceType=SAMSUNGGTI9500 HTTP/1.1" 502 434 "-"  
> "SAMSUNG-GT-I9500/101.40202"
>
> 59.167.157.243 - - [09/Jun/2013:20:56:36 +1000] "POST  
> /Microsoft-Server-ActiveSync?Cmd=Ping&User=simon%40simonandkate.net&DeviceId=SEC10D1C297BE813&DeviceType=SAMSUNGGTI9500 HTTP/1.1" 502 434 "-"  
> "SAMSUNG-GT-I9500/101.40202"
>
> 59.167.157.243 - - [09/Jun/2013:20:58:39 +1000] "POST  
> /Microsoft-Server-ActiveSync?Cmd=Ping&User=simon%40simonandkate.net&DeviceId=SEC10D1C297BE813&DeviceType=SAMSUNGGTI9500 HTTP/1.1" 502 434 "-"  
> "SAMSUNG-GT-I9500/101.40202"

These are almost certainly a result of the proxy timeout being reached  
before the PING has finished running on the server. If you google for  
something like "apache reverseproxy activesync 502" you will find  
information regarding this and how to fix it.

> So my Samsung S4 is sending that POST request every minute or two  
> (seems excessive?)

This is because the device is sensing that the PING failed or the  
connection dropped, so it retries it again. At some point, the client  
is supposed to throttle itself.

> and it is logged by the proxy server, and every time it is followed  
> 120 seconds later by the proxy server logging the pair of errors,  
> and a 502 recorded by the proxy.
>
> The internal Horde server appears to be receiving the requests. e.g.:
>
> 192.168.1.155 - simon at simonandkate.net [09/Jun/2013:20:58:37 +1000]  
> "POST  
> /Microsoft-Server-ActiveSync?Cmd=Ping&User=simon%40simonandkate.net&DeviceId=SEC10D1C297BE813&DeviceType=SAMSUNGGTI9500 HTTP/1.1" 200  
> -
>
> The Horde server's Apache error logs are empty, so it is happy that  
> it's done what it needs to (200 result), but for some reason it's  
> not sending something back to the proxy. The Samsung ActiveSync  
> functionally is working fine.
>
>
> When my Apple devices Post, e.g.:
>
>
> 59.167.157.243 - - [09/Jun/2013:21:06:24 +1000] "POST  
> /Microsoft-Server-ActiveSync?User=katie&DeviceId=ApplDLXFT8GMDKNW&DeviceType=iPad&Cmd=Ping HTTP/1.1" 200 27 "-"  
> "Apple-iPad2C2/1002.329"
>
> It's doing it approximately every 10 to 15 minutes (as opposed to  
> every 1 or 2 for the Samsung).
>
> This is the corresponding request on the Horde internal box:
>
> 192.168.1.155 - katie [09/Jun/2013:21:06:22 +1000] "POST  
> /Microsoft-Server-ActiveSync?User=katie&DeviceId=ApplDLXFT8GMDKNW&DeviceType=iPad&Cmd=Ping HTTP/1.1" 200  
> 27
>
> So that is complete end to end with 200s.
>
>
> Something about the Samsung's POST request or the way it is being  
> handled by the proxy or Horde is causing it to get 502s and generate  
> errors, where the Apples requests complete fine. As a result, the  
> Samsung is POSTing every 1 or 2 minutes...

Either because the heartbeat interval is different for each client or  
it's coincidence that the PING ended naturally due to a detected  
change when the iOS device was being watched.

-- 
mike

The Horde Project (www.horde.org)
mrubinsk at horde.org
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