Solved

Network connectivity keeps dropping out on this switch...

Posted on 2008-10-01
7
385 Views
Last Modified: 2012-05-05
We've got a rack of 3coms, and one in particular (THAT I HAVE ALREADY SWAPPED OUT), seems to be OK for about 10 minutes or so (judging by the Windows 2003 Server DHCP logs), and then nothing.  No connectivity after a few minutes or so.  The LEDs on the switch don't seem to suggest anything weird.

Strangest part is, the computers CANNOT receive an IP when connected through this switch, but can connect when given a static IP.  But I swapped the switch out for another and they all had received dynamic IPs, but now 20 mins later, they are unable to talk to anything...

Any ideas????
0
Comment
Question by:tru504187211
  • 4
  • 3
7 Comments
 
LVL 5

Expert Comment

by:ccns
ID: 22620370
I would suggest changing the cable that links the switches together ? possible that this could be the issues unless the server is also plugged in to the failing switch?
0
 

Author Comment

by:tru504187211
ID: 22620409
Done that as well...still nothing.
0
 
LVL 5

Expert Comment

by:ccns
ID: 22620423
rack of 3coms, do they connect into some sort of backbone thing at the rear of the switch or is it just a rack situation. switches one above the other connected via cable/fibre
0
Give your grad a cloud of their own!

With up to 8TB of storage, give your favorite graduate their own personal cloud to centralize all their photos, videos and music in one safe place. They can save, sync and share all their stuff, and automatic photo backup helps free up space on their smartphone and tablet.

 

Author Comment

by:tru504187211
ID: 22620447
Yes, the network is a star with a 3com 4200g as the backbone.  All of the other switches com off of here in a star pattern (4200g being the center).
0
 
LVL 5

Expert Comment

by:ccns
ID: 22620465
can you log onto the backbone 4200g and possibly look at the status of the port where the trouble switch is plugged into. see if it comes up with errors etc? you have already changed cables.. what about ports?
0
 

Author Comment

by:tru504187211
ID: 22750447
Yes, I've logged into the 4200 backbone and it reports all 28 ports are either open or OK.  NOW, mutliple switches are dropping off with no warning.  Only similarity, is that they are all gigabit switches that are failing...

Also, scrap that idea about static IP's working.  I've now verified that to be false...

Again, the switches are fine for a while after they are power cycled.  Wireshark is not coming up with anything much except all different clients asking who belongs to this or that IP.  Every once in a while, one machine hammers the network with broadcasts, but I cannot figure that one out yet, but it does not seem to force any switches offline at that time, that I can tell...
0
 

Accepted Solution

by:
tru504187211 earned 0 total points
ID: 22805190
Solution turned out to unplug ONE cable...someone had thrown a loop in the network from a network cable that used to be connected to a computer...

Thanks!
0

Featured Post

Zoho SalesIQ

Hassle-free live chat software re-imagined for business growth. 2 users, always free.

Join & Write a Comment

Suggested Solutions

In this tutorial I will show you with short command examples how to obtain a packet footprint of all traffic flowing thru your Juniper device running ScreenOS. I do not know the exact firmware requirement, but I think the fprofile command is availab…
I eventually solved a perplexing problem setting up telnet for a new switch.  I installed a new Cisco WS-03560X-24P switch connected to an existing Cisco 4506 running a WS-X4013-10GE Sup II-Plus. After configuring vlans and trunking,  I could no…
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…
This video shows how to remove a single email address from the Outlook 2010 Auto Suggestion memory. NOTE: For Outlook 2016 and 2013 perform the exact same steps. Open a new email: Click the New email button in Outlook. Start typing the address: …

760 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

22 Experts available now in Live!

Get 1:1 Help Now