LansITGuy

Turned off the router in the staff room with no change in ping resposnes to the effected routers. The strange thing is that users logins are not being slowed down to the same level they were yesterday. I am fairly sure that there is some problem somewhere with the link between my office cab and the one containing the effected router. There are excessive communication errors being logged in the routers consoles passing down the chain of connected ports 25 & 26, but it is only the 3rd router in the cab which has the intermittant communication issues. The switches are quite well spaced and ventilated so I don't think we have an overheating issue. I may trying rewiring the cab round as the 4th switch doesn't seem to have any active connections and so I can move all of switch 3 cables into it to see what happens.

Thanks for the help Matt. Ok, the DHCP for the network is 172.16.0.1. I think there may have been a D-Link router used to add network ports in our staff room. Just going to head off to power it down. Hopefully we may be on to something. Cheers.

Ok, the 10 range is our Admin network which has a domain trust with the curriculum side. The 198 and 212 ranges? Good question.... Time to start digging.

I have run a few tests using the Wireshark program. Although I am not sure exactly what I would expect to find on a network loopback, the only errors I am seeing are coming from my own computer 8O . Using the Analyze – Expert Info tool I am getting a large number of Bad Checksum values. Just in case this was causing problems I have disconnected my own PC from the network, but the previously reported situation remains the same. If anyone has a spare second I have attached a 1 minute sample output file. For reference the computer running Wireshark is on IP 172.16.1.9. Thanks again everyone for your continued help. hc_1min_sample.rar

Thanks for the replies. This just keeps getting stranger. Whilst no one else was in school today I disabled all the ports with a view of starting them consecutively to see which port gave an issue. Even though the main PC ports were disabled I was still getting an intermittent ping loss when trying to contact the 3rd switch. I am really starting to think that it is the 2nd switch in the stack. To test this I bypassed switch 2 and so had 1 connected to 3. This seems to resolve the issue (apart from leaving me 24 connections down). Thinking that this may have been a cable fault I reset the connection between 2 and 3 with a new cable. This seemed to clear the issue at first but now I’m back in the office it appears to have started again (18%) packet loss. As a point of interested I have tested the removed network cable and it is working correctly. I really don’t think there is a loop back on the network. In the past this has stopped nearly all network activity and I’m just not seeing the same effects. I will try getting hold of the WireShark and Ethereal tools to see what happens. It’s going to be a long day :? . Thanks for the help guys. Any more suggestions are welcome.

Good afternoon. I hope someone out there would be kind enough to help me. This post may drag on a little as I try and explain the situation. I don’t have much experience in solving networking issues like this so I’m not too sure what info is needed. We currently have some quite major network connection issues in some of our rooms. This has been traced back to one of the cabinets which contains 4 switches. It appears that all ports in the cab are in some way affected. I have attempted to ping all 4 switches. The top 2 respond as normal but switches 3 and 4 have very intermittent ping responses with over 75% packet loss. Switch 1 is connected to another router in my office and then connected to switch 2. Switch 2 is connected to switch 3, then switch 3 to switch 4. I have disconnected each cable from switch 3 in turn but the response rate does not appear to change. I have tested the connection cable between switch 2 and 3 which is working correctly. At first I thought this was being caused by a feedback loop. However, the last time this happened in school the whole network was affected, but this time it is a much smaller area. All switches are ProCurve 2626. I have logged into the web consoles and the software is reporting some errors (on these and other switches not listed above) including excessive jabbering and excessive broadcasts. There have been no network changes made in the past couple of weeks, but this problem only seems to have started last Friday. Why is only a section of the network being effected? What can I do to trace and resolve this problem? Any suggestions would be very much appreciated. Thanks for your time. Mike.

Ah, the MMC is out too... Looks like a reboot is the only option. Will need to wait until the end of the day though because it's the server with all the user home directories. Always the way. Thanks for the help.

Thanks for the quick reply. Good point. Unfortunatly the Services window will not open either :oops: Is there a command line alternative to see what services have started?

Hi everyone. Hope someone out there could be so kind as to give me a little guidance about a problem I seem to have with one of our servers. This morning I have had to reboot the server because of some slow network issues yesterday. Everything seemed to reboot as normal so I logged in with my account and our Ranger server kicked in as expected. The problems seem to have arisen when a pupil came in to my office to request a password reset. I attempted to open Active Directory Users & Computers. The hour glass appeared for a second then returned to the mouse pointer but the window never opened. To check what was running I attempted to open Task Manager with the same problem as above. The CPU graph appears by the clock for a few seconds and then disappears. I also tried to open Event Viewer with the same response. Other non Server 2003 included apps seem to run (such as our copy of Veritas). No major changes have been made to the server prior to the reboot. Does anyone have any ideas how this could have happened or how to get passed it? My other servers are fine, it’s just the one. Thanks in advance. Regards: Mike.