Metric Collection Error oracle.sysman.emSDK.emd.comm.CommException: Cannot establish proxy connection: 503 Service Unavailable No route to host

In Oracle Enterprise Manager Grid Control, the Agents, Hosts, Listeners were all displaying correctly with status of ‘up’.

But the databases reported status of “Metric Collection Error”.

When I tried to configure a database, the configure database page displayed either one of these errors at top of page:

oracle.sysman.emSDK.emd.comm.CommException: Cannot establish proxy connection: 503 Service Unavailable

oracle.sysman.emSDK.emd.comm.CommException: No route to host

Problem was agent server firewall settings blocking ports.

Fix for me was:

1) on agent server as oracle

cd /software/oracle/product/agent10g/bin
./emctl status agent

Look for “Agent URL” in the output of that command, in my case that was


2) On Grid Control server as oracle, paste that line into a wget command at the command prompt:

wget --no-check-certificate https://myagentserver.mydomain:3872/emd/main

That failed with: “failed: No route to host”, fix was as below:

3) On agent server again – as root

Make backup copy before changing settings:

cd /etc/sysconfig
cp -p iptables iptables.backup
vi /etc/sysconfig/iptables

Add a new line for port 3872 by copying one of the existing lines, e.g.:

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3872 -j ACCEPT

Restart with:

service iptables restart

This worked for me with Oracle Enterprise Manager Grid Control and Agent both version and both on 32 bit linux.

May 21, 2010

  • I’ve seen a similar issue with error “route to host missing” . not sure if anyone else has.

  • This resolution resolved my Grid Control problem. Apparently, even though the port stated it was listening, the firewall was still blocking connections until I added this entry into my iptables.

  • Yes it works for me..! Agent was running and uploading successfully but discovery failing with ‘NoRouteToHostException: No route to host’. Finally adding agent port entry in entry into my iptables resolved issue. Thnaks..!

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