On Tue, 2011-03-29 at 05:13 +0800, mcclnx mcc wrote: > we have several servers on same rack and servers are all inside firewall. Centos version from 4.X to 5.X. sometime the connection are very slow (compare to servers on other racks also inside firewall). > > we discuss with network engineer he ask us use "ping" and traceroute" to check. Both tools response time are good but if we connect through application like Web browser, database, or DELL OPMN tool. The response time is very very slow. > > This situation normally last 4 to 5 hours then it back to normal. Does there has way to check "real" network response time so we can show to network engineer. Otherwise they always say "no problem". miitool and ethtool Check that you're running at the right speed; sometimes bad cables will make the negotiation go bad. Sometimes you just connect to the wrong switch port. You may also note if the switch has hard-set values about the negotiation such as duplex settings. Make sure they match on both ends. You should be full duplex unless there's a very very good network reason not to. Lastly, check ifconfig output. Make sure there's no errors reported. If you have a high error count, it's a good bet the cable is bad or the sync settings are wrong. -- Best Regards Peter Larsen Wise words of the day: Showing up is 80% of life. -- Woody Allen -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: This is a digitally signed message part URL: <http://lists.centos.org/pipermail/centos/attachments/20110328/5b2ec841/attachment-0005.sig>