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CW: Hostname instead of IP-addresses in syslog.log

rolf.fischer_2
Level 1
Level 1

Recently we updated our CiscoWorks server from LMS 2.5 to 2.6.

Since we use the newer version, the appearance of the syslog.log has changed: The devices are listed by their IP-addresses, earlier we saw their (DNS-) hostnames.

We run a simple script every morning which generates a 24 hour syslog-summary from the syslog.log and emails it to the administrators. Earlier this email showed hostnames, now it shows IP-addresses which are not very readable/meaningful.

The report which CW generates in a browser-window shows hostnames, not IPs.

We already checked DNS on the CW-server, it works properly (reverse also).

Is there a way to make the CW-syslogserver log the hostnames instead of the IPs?

Thanks in advance,

Rolf

5 Replies 5

Joe Clarke
Cisco Employee
Cisco Employee

In LMS 2.6, enabling syslog DNS resolution is very easy. Go to Common Services > Server > Admin > System Preferences, and check the box for "Enable crmlogger DNS resolution." Be aware, though, that enabling this may have a performance impact depending on the volume of messages you are receiving.

Thank you for the quick response!

I'll give it a try tomorow when I'm in the office. Rating follows.

You mention a potential performance impact. That sounds very comprehensible.

Are there any experience values of "how much is too much"?

Thanks again.

We recommend no more than 200 messages per second with bursts to 1000. Without knowing the latency involved with your DNS resolution, I cannot comment on how many messages per second until you start seeing issues, but if you're receiving 50 messages per second, and it takes 1 second to do a lookup, you're actually receiving 100 per second. So DNS will effectively cut your total message capacity.

Thank you once again!

Unfortunately I didn't find the checkbox for enabling DNS resulution.

My fault! We're still running LMS2.5 - 2.6 is ordered but not yet installed.

Is there a way to do the same with LMS2.5?

Yes, but you need to manually edit the registry. The key is HKLM\SYSTEM\CurrentControlSet\Services\crmlog\Parameters\CrmDnsResolution. Set this to 1, and restart the CiscoWorks syslog service.