Error: 502 bad gateway in Apache Reverse Proxy Web Agent
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Error: 502 bad gateway in Apache Reverse Proxy Web Agent

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Article ID: 260737

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Updated On:

Products

SITEMINDER CA Single Sign On Agents (SiteMinder) CA Single Sign On Secure Proxy Server (SiteMinder)

Issue/Introduction

 

Running CA Access Gateway (SPS), this one returns the error:    

502 bad gateway

Error lines are seen:

[Sun Feb 12 23:32:27.867394 2023] [proxy:error] [pid 80769:tid 139704280217344] (70007)The timeout specified has expired: AH00957: HTTPS: attempt to connect to 10.0.0.1:443 (_host._domain._com) failed
[Sun Feb 12 23:32:27.867432 2023] [proxy_http:error] [pid 80769:tid 139704280217344] [client 10.0.0.100:26340] AH01114: HTTP: failed to make connection to backend: _host._domain._com

Cause

 

At first glance, error 502 bad gateway might be caused by a network problem as Mozilla documentation (1).

It's similar to the error 504 related to this KD caused by network problems (2).

Looking at the logs, the problem is outside SiteMinder and the Web Agent.

As Apache is a reverse proxy, the issue is that the backend server doesn't return the expected data to the Apache reverse proxy.

The server _backhost._domain._com:443 doesn't return expected data from application /myApp/myPage.html to the Apache on which the Web Agent runs:

error.log:

[Sun Feb 12 22:48:57.441179 2023] [proxy:error] [pid 2121:tid 140696862312192] [client 10.0.0.101:11672] AH00898: Error reading from remote server returned by /myApp/myPage.html
[Sun Feb 12 22:49:42.492130 2023] [proxy_http:error] [pid 2121:tid 140696870704896] (70007)The timeout specified has expired: [client 10.0.0.101:52944] AH01102: error reading status line from remote server _backhost._domain._com:443

[...omitted for brevity...]

[Sun Feb 12 22:53:50.757169 2023] [proxy_http:error] [pid 2121:tid 140696753207040] (70007)The timeout specified has expired: [client 10.0.0.101:5185] AH01102: error reading status line from remote server _backhost._domain._com:443
[Sun Feb 12 22:53:50.757189 2023] [proxy:error] [pid 2121:tid 140696753207040] [client 10.0.0.101:5185] AH00898: Error reading from remote server returned by /myApp/myPage.html

The server mysecondbackendserver.mydomain.com:443 doesn't return expected data from application /myapplication/ to the Apache on which the Web Agent runs:

error.log

[Sun Feb 12 22:30:33.803632 2023] [proxy_http:error] [pid 206802:tid 140613512865536] (70007)The timeout specified has expired: [client 10.0.0.102:7604] AH01102: error reading status line from remote server mysecondbackendserver.mydomain.com:443, referer: https://_apphost._domain._com/
[Sun Feb 12 22:30:33.803667 2023] [proxy:error] [pid 206802:tid 140613512865536] [client 10.0.0.102:7604] AH00898: Error reading from remote server returned by /myapplication/, referer: https://_apphost._domain._com/

[...omitted for brevity...]

[Sun Feb 12 23:45:43.889600 2023] [proxy_http:error] [pid 10036:tid 140613269780224] (70007)The timeout specified has expired: [client 10.0.0.103:40224] AH01102: error reading status line from remote server mysecondbackendserver.mydomain.com:443, referer: https://_otherhost._domain._com/
[Sun Feb 12 23:45:43.889635 2023] [proxy:error] [pid 10036:tid 140613269780224] [client 10.0.0.103:40224] AH00898: Error reading from remote server returned by /myapplication/, referer: https://_otherhost._domain._com/

Resolution

 

Investigate with network team and the backend servers team why the backend server was unable to return the expected data to the Apache Reverse Proxy to solve this issue.

 

Additional Information

 

(1)
 
    
    
(2)
 
    
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