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Does EN104- Hub learn which IP Adress is on which Port?

MorkvomOrk
Aspirant

Does EN104- Hub learn which IP Adress is on which Port?

We want to use an EN104 Hub to monitor our network traffic and analyze the packages with Wireshark.

We connected the hub in between two network devices and connected one laptop with the hub so that the hub can do what it's suppoesed to do and sends all packages to all connected devices.

 

One Day it worked, the next day it didn't.

We tried everything, from Updating Wireshark to unplug all cables from the hub and replug them in another order.

Only thing that helped was switching the laptop to another one that has never been connected to the hub.

When we reconnected the first laptop on the fouth port it did not work either.

 

It is as if the hub learns what Mac Adress is connected to which Ip- Adress and on which Port, so that it does not work as a real hub all the time.

 

*IMPORTANT NOTICE*

Before someone complains, this is 100% legal, because we own both devices and we wrote the both the softwares that are sending data over the network cable.

In a machine that is running at a site of our customer, we have difficulties receiving the data we sent in the correct order, so we want to use that configuration of a hub and a laptop to analyze the network at our customers site to find the part of the network thats causing the information loss.

 

Thanks in advance

Message 1 of 7

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MorkvomOrk
Aspirant

Betreff: Does EN104- Hub learn which IP Adress is on which Port?

A Short Update on that Topic,

 

we figured out that he system works properly when we're not using DHCP given Adresses but use adresses that are fixed in all the devices that are connected to the Hub.

With that he is working correctly. If we use devices that have adresses given by DHCP it stops working as a HUB uncontrollably, sometimes it's working for an hour, sometimes more and most times less than. He's still trasmitting the data, but not to all devices like it should do.

 

The topic can be closed, we found a solution.

Thanks to all contributors.

View solution in original post

Message 6 of 7

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JohnRo
NETGEAR Employee Retired

Re: Does EN104- Hub learn which IP Adress is on which Port?

Hello MorkvomOrk, 

 

Welcome to the community! 

 

I understand you have some questions regarding one of our older model hubs. To answer your question, this hub does NOT have any capability to remember IP addressing and does not even have a MAC address table. The hub send broadcast to all of the ports to pass the packet and basically only function on physical layer. 

 

I hope this answer your question. If you have more inquiries, the community will be happy to help. 

 

Thanks, 

JohnRo
NETGEAR® Community Team
Message 2 of 7
SamirD
Prodigy

Re: Does EN104- Hub learn which IP Adress is on which Port?

Only thing I would check is if the hub is working correctly.  This is a very old product (I have 3 of them), so it may not be working correctly. 

Message 3 of 7
MorkvomOrk
Aspirant

Betreff: Does EN104- Hub learn which IP Adress is on which Port?

Hello JohnRo,

 

Thank you for your answer. Basically you told me what i thought a normal Hub would work like.

 

But that is not what we were seeing. After one day of working perfectly fine, the Hub does not send the Data to all connected machines anymore. Like i said, it looked as if it was learning which machine is on which Port.

 

In the meantime, we figured out that we could make the system work again when we change the IP Adress on that laptop to another one that was not connected to that Hub so far.

This means going from a DHCP based System to a mixed system with IP Adresses distributed by DHCP and some are fixed.

Our admin was not amused but we told him and he was telling us the same thing, but also could not figure out what was happening with that Hub.

 

But anyway, thanks for your help.

 

Hi SamirD,

 

What do you mean by  "working correctly"? Because of it not working correctly i started this tread in the first place. 

I have to say, i honestly don't know how to check if a hub works correctly?

It has some LEDs that were blinking, but if data was going over it not all of them were flashing simultaneously. Is that what you meant?

 

We reconnected all of the cables including the power supply so the Hub could restart, but it did not work.

 

Also, thanks for your help.

 

Like i already wrote, we figured out that changing the IP Adress helps with the issue, but i'm still interested how's it possible why a Hub shows behaviour that it should not be able to.

 

Message 4 of 7
SamirD
Prodigy

Betreff: Does EN104- Hub learn which IP Adress is on which Port?

So on mine, I discovered excessive collisions and long ping times during testing.  Found out that the power supply wasn't delivering the proper number of amps.  If you have another power supply that meets the specs, I'd try it.  (And if it's rated for more amps, that's fine too as the hub will only draw as much power as needed.)

Message 5 of 7
MorkvomOrk
Aspirant

Betreff: Does EN104- Hub learn which IP Adress is on which Port?

A Short Update on that Topic,

 

we figured out that he system works properly when we're not using DHCP given Adresses but use adresses that are fixed in all the devices that are connected to the Hub.

With that he is working correctly. If we use devices that have adresses given by DHCP it stops working as a HUB uncontrollably, sometimes it's working for an hour, sometimes more and most times less than. He's still trasmitting the data, but not to all devices like it should do.

 

The topic can be closed, we found a solution.

Thanks to all contributors.

Message 6 of 7
SamirD
Prodigy

Betreff: Does EN104- Hub learn which IP Adress is on which Port?

Thank you for posting your findings.  I'll be sure to watch for these type of issues on my en104s.

Message 7 of 7
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