gig switch not work but 100mb will

Posted on 2015-01-14
Last Modified: 2015-03-12
i have an imac computer and when i connect it to a gig switch, there is no connection. when i connect it to a 10/100 switch it works. can anyone tell me why?
this also happened when i tried to connect a 10/100 to a gig switch.
Question by:stevekee65
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 13

Expert Comment

by:Mark Galvin
ID: 40549117
So, in summary:
iMac does not work on gig switch
iMac works on 10/100 swtich

When you state 'this also happened when i tried to connect a 10/100 to a gig switch' what test/s are you referring to?

What model (year) is the iMac?
LVL 13

Expert Comment

by:Mark Galvin
ID: 40549122
PS all macs since g4 come with gigbit as Apple was an early adopter.

Author Comment

ID: 40549175
when i connect a linksys 24 port switch to the gig switch and it would act as if there were no connection. i believe it is one of the aluminum imacs.
MIM Survival Guide for Service Desk Managers

Major incidents can send mastered service desk processes into disorder. Systems and tools produce the data needed to resolve these incidents, but your challenge is getting that information to the right people fast. Check out the Survival Guide and begin bringing order to chaos.

LVL 13

Expert Comment

by:Mark Galvin
ID: 40549176
So really, anything you plug into the gig switch doesnt work?

Author Comment

ID: 40549183
there are other computers connected to that gig switch. i connected the imac to all of the gig switches we have and nothing. i connect it to a 10/100 switch and it works
LVL 13

Accepted Solution

Mark Galvin earned 250 total points
ID: 40549203
I would check the speed & duplex setting on the iMac. All gig switches should be set to auto/auto. It might be that the iMac has been hard set to 100/full or something which would mean conencting to to a gig switch would mean no auto neg.

What version of Mac OS is this on?
LVL 13

Expert Comment

by:Mark Galvin
ID: 40549235
Here is a link that would help for Mavericks
LVL 95

Assisted Solution

by:Lee W, MVP
Lee W, MVP earned 250 total points
ID: 40549339
Check your cabling.  Gig ethernet requires Cat5e or better cabling, patch panels, and connectors.  If any of these are older, you can have problems - I've seen issues where things don't connect, they do connect but fail to negotiate and just keep saying connecting.... (Windows), and go out intermittently.  First thing I'd do is verify your cabling.

Expert Comment

by:nader alkahtani
ID: 40549754
Check cable if it compatible with GIG and the connectors

Expert Comment

by:corey tauriac
ID: 40601695

   Looks like this has been an issue for quite a while.  Most people were able to solve it by having the logic board changed out, but if this is an older model obviously that probably wouldn't so useful, but at least it works at 10/100.  For the most part and majority ruled on this one being most likely an issue with the logic board.

Featured Post

Manage your data center from practically anywhere

The KN8164V features HD resolution of 1920 x 1200, FIPS 140-2 with level 1 security standards and virtual media transmissions at twice the speed. Built for reliability, the KN series provides local console and remote over IP access, ensuring 24/7 availability to all servers.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How do you do a firmware update on HP Proliant Servers? Smart update manager? 3 67
what is mstp 6 60
Bandwidth cap???? 8 56
Rogue RDP Connections 5 54
Join Greg Farro and Ethan Banks from Packet Pushers ( and Greg Ross from Paessler ( for a discussion about smart network …
This article will inform Clients about common and important expectations from the freelancers (Experts) who are looking at your Gig.
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor ( If you're looking for how to monitor bandwidth using netflow or packet s…

740 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