Symptoms
The following error message appears in the Application Event Log:
Event ID: 103 - "An error occurred when processing incoming CGP downstream data."
Source: Reliability Server
These errors occur even if there are no sessions on the server. They begin to appear after Hotfix Rollup Pack 1 for Citrix Presentation Server 4.5 was installed. The errors remain even if Hotfix Rollup Pack 1 is removed.
In the XTE log the same errors appear:
[Fri Jul 20 15:51:14 2007] [notice] Server built: Jan 24 2007 23:31:11
[Fri Jul 20 15:51:14 2007] [notice] Parent: Created child process 4500
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Child process is running
[Fri Jul 20 15:50:57 2007] [notice] async engine initialized successfully,
8 worker threads started
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Acquired the start mutex.
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Starting 150 worker
threads.
[Fri Jul 20 15:53:46 2007] [error] (70014)End of file found: An error
occurred when processing incoming CGP downstream data
[Fri Jul 20 15:53:46 2007] [error] (70014)End of file found: S 0x7AAA08:
ap_get_brigade failed
[Fri Jul 20 15:58:38 2007] [error] (70014)End of file found: An error
occurred when processing incoming CGP downstream data
[Fri Jul 20 15:58:38 2007] [error] (70014)End of file found: S 0x7A9FE8:
A CDF trace shows that there is an incoming connection at the time the error occurs.
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: START, connection ID=149 allocating conn_rec
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: c->pool=00673068
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: local_ip=172.18.4.58
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: remote_ip=172.18.4.153
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: setting bucket_alloc=00675070
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: FINISH
mod_socks 09/21/2007 02:54:11.132 socks_client_pre_connection START
mod_socks 09/21/2007 02:54:11.132 socks_client_pre_connection no destination - return OK
mod_multiplexer 09/21/2007 02:54:11.132 process_multiplexer_connection: START
mod_multiplexer 09/21/2007 02:54:11.132 process_multiplexer_connection: no need to enable multiplexing on this connection, FINISH
mod_cgp 09/21/2007 02:59:11.218 process_cgp_connection start
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 request: create_request conn=0x66B158 conn->pool=0x66B048
mod_cgp 09/21/2007 02:59:11.218 request: create_request START created request pool from conn pool, r->pool=0x30D1048
mod_cgp 09/21/2007 02:59:11.218 request: calling ap_run_create_request to let other hooks run
mod_cgp 09/21/2007 02:59:11.218 request: create_request FINISH, returning request_rec
mod_cgp 09/21/2007 02:59:11.218 request: destroy_request destroy request pool r->pool=0x30D1048
mod_cgp 09/21/2007 02:59:11.218 UnlockSessionEntry : Unlock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead enter: session=0x7a9ff0 Downstream
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead:got an empty brigade
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead exit
mod_cgp 09/21/2007 02:59:11.218 UnlockSessionEntry : Unlock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead enter: session=0x7a9ff0 Downstream
mod_cgp 09/21/2007 02:59:11.220 ProcessSocketRead:ap_get_brigade failed
mod_cgp 09/21/2007 02:59:11.220 ProcessSocketRead exit
mod_cgp 09/21/2007 02:59:11.220 cgp_close_socket enter sock=0x66B090
mod_cgp 09/21/2007 02:59:11.220 cgp_close_socket exit
mod_cgp 09/21/2007 02:59:11.220 cgp_destory_session enter
mod_cgp 09/21/2007 02:59:11.220 cgp_destroy_session:Destroying session 0x7A9FF0
mod_cgp 09/21/2007 02:59:11.220 Session 0x0: CGPSDK: CGPCore: CgpDestroySession called with invalid session handle.
mod_cgp 09/21/2007 02:59:11.220 cgp_destory_session exit
mod_cgp 09/21/2007 02:59:11.220 UnlockSessionEntry : Unlock session 0x0 (lock: 0x6645C8).
Cause
The server IP 172.18.4.153 is a Nagios Monitoring Server. Beside other things it scans ports 80, 1494, and 2598 on the servers running Presentation Server. The scan of port 2598 causes the XTE service to receive unexpected data, which is why the error message is written to the Event Log.
This can be reproduced by using telnet from the command line:
c:\>telnet 172.18.4.58 2598
Resolution
The event log messages appear in the event log due to extra monitoring that is enabled in Presentation Server 4.5. You can use the following procedure to disable the error messages by logging only emergency errors.
1. Edit the C:\Program Files\Citrix\XTE\conf\httpd.conf file as follows. The lines to add are bold.
#CGP Listen Port
Listen 2598
# Log Level
loglevel emerg
2. Restart the XTE service for the change to take effect.
Status
The Event ID message is benign and as per design.
More Information
This same error may appear on the Secure Gateway Servers Event Viewer Secure Gateway Logs:
“Event Type: Error
Event Source: Secure Gateway
Event Category: CGP
Event ID: 103
Date: 11/9/2007
Time: 2:41:11 PM
User: N/A
Computer: YourCSGServer
Description: Incoming Citrix Gateway Protocol downstream data could not be processed.”
This message can easily be reproduced by stopping the Citrix XTE Service on the server running Presentation Server. The client receives the error outlined in CTX106531 – Troubleshooting the Citrix XTE Service and Errors: There is no route to the specified address ... Protocol Driver Error.
You can find information on editing the http.conf file at the following Web site:
Configuration Directives in httpd.conf
LogLevel can be set (from the least detail to the most detail) as follows:
emerg (emergency)
alert
crit (critical)
error
warn (warning)
notice
info
debug
The default LogLevel setting is warn.
