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FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast

Can you insert a switch between modem and router?

I have a TM722, and I am trying to insert a switch between it and my router just for testing purposes.

Problem is when I do, my router will NOT pull an IP address.

I hook router straight to modem, its fine.

Should this work?

Thanks,

-Alan



Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
kudos:9

Switches are connected normally after the router; not in between the modem & router.


timtom

join:2012-11-15
reply to FirebirdTN

said by FirebirdTN:

I have a TM722, and I am trying to insert a switch between it and my router just for testing purposes.

Problem is when I do, my router will NOT pull an IP address.

I hook router straight to modem, its fine.

Should this work?

Thanks,

-Alan

What do you want to test.
Do you know how switch works.
I dont get it why would you do that if you have no knowledge about it


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9
reply to FirebirdTN

Try using the recessed reset button on the rear of the TM722. You'll need something like a bent paper clip or a pen tip. Depress and hold in the recessed reset button on the rear until you see the front panel indicator lights begin to cycle, then release. Now give the eMTA the time it needs to re-sync.


FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1

EG-THANK YOU for actually reading my whole original post, and offering some helpful advice.

Unfortunately, I already did that and no IP address.

-Alan



Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
kudos:9

What are you trying to do if I may ask?


FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast

Its complicated. I have another thread, but I have found the more details you put in a post, the less people actually READ it.

The bottom line is I am trying to nail down some intermittent connectivity issues, which is stemming from packet loss.

-Alan



Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
kudos:9

I gave you the straight forward on placement of a switch. Now, if you want members to help with your EXP., it would probably be best to detail your issue, the theory behind your connection strategy & what you hope to accomplish.


FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast

Okay...

All I have available to me at the moment is a switch, but tomorrow I'll probably bring a network hub home from work (it will kill my speed, but c'est la vie).

I plan to insert the hub between the router WAN and modem, and use wireshark to sniff the packets transversing my network.

Or at the very least, when my "outage" occurs, I could jump on the computer connected straight to the modem via the hub/switch and see if it has an "outage" as well (assuming comcast will let me occupy two public IP addresses).

I am at the troubleshooting step where I need to hook a PC directly to my modem, bypassing my equipment. Problem is, 1) that is nearly impossible to do at this household and 2) I can't actually use the connection in a normal fashion this way. So if I can't "stress" the modem/connection because only a single computer is connected to it, it doesn't really prove anything.

-Alan



Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
kudos:9

Unless you are in a select residential area where you can purchase additional IPs or have a business account, you will not be able to pull an additional IP.


FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast

THAT is what I needed to know.

If I can't pull two IPs, then jumping to the "direct" connected PC during one of my "mico outages" is out of the question.

Doesn't explain why I still can't pull a single IP with my router when a switch is inserted between it and the modem though. I can still pull off wireshark packet sniffing without a 2nd IP (I think-its been a while), but the router would HAVE to get the IP thru the hub/switch for it to work.

-Alan



56885201
Ain't Nothin' But A Hound Dawg
Premium
join:2005-05-01
Dawg House

2 recommendations

reply to FirebirdTN

You are probably using a smart (or semi-smart) switch that has a visible MAC address. With a residential account (assuming you are only paying for one IP address), only one MAC address is allowed to be visible to the cable modem.

I have a Netgear GS108E that is a semi-smart switch (it has limited configuration capabilities), and if it is directly behind my cable modem, the modem sees the switch MAC address, and that then limits the number of devices that I can connect to the switch (I have a 5 IP address account, but that actually means a 5 MAC address account). The reason is that the modem looks at MAC addresses, and how many it can allow is controlled by the config file. It makes no difference if the switch uses DHCP, or has a static IP address; if it has a visible MAC address, the modem will count it as one of your allowable connected devices (which for most residential accounts is only one device).

I used to use the Netgear GS108E for its QoS capabilities, but I had to replace it with a ZyXEL switch that had fixed port priority QoS, and did not have user configurable settings (and no visible MAC address), because sometimes I needed to have 5 payload devices connected, and the Netgear GS108E would interfere with being able to do that.
--
Some days you're the dog; some days you're the hydrant.


FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1
Reviews:
·Comcast

1 edit

Cool Dawg-THANK YOU THANK YOU THANK YOU!

I am on a residential connection (single, dynamic IP). My switch isn't a managed switch, but I think you probably hit the nail on the head.

Matter of fact, its a 5 port ZyXel GS-105 (Gig-E). I suspect it does have its own MAC, but I don't know that for certain.

I'll give the old dumb hub a try tomorrow.

-Alan

-EDIT- Yup, I'm officially an idiot. This isn't a "smart" (managed) switch, but I just looked on the bottom; it DOES indeed have its own MAC.



jack b
Gone Fishing
Premium,MVM
join:2000-09-08
Cape Cod
kudos:1

What you're trying wont work because the switch can't "pull" an IP address even if it has a mac address.



56885201
Ain't Nothin' But A Hound Dawg
Premium
join:2005-05-01
Dawg House
reply to FirebirdTN

said by FirebirdTN:

Cool Dawg-THANK YOU THANK YOU THANK YOU!

I am on a residential connection (single, dynamic IP). My switch isn't a managed switch, but I think you probably hit the nail on the head.

Matter of fact, its a 5 port ZyXel GS-105 (Gig-E). I suspect it does have its own MAC, but I don't know that for certain.

I'll give the old dumb hub a try tomorrow.

-Alan

-EDIT- Yup, I'm officially an idiot. This isn't a "smart" (managed) switch, but I just looked on the bottom; it DOES indeed have its own MAC.

That is very interesting. I switched from using a Netgear GS108E to using a ZyXEL GS105S. The GS105S does have a MAC address listed on its printed label, but (unlike the Netgear GS108E), it does not seem to be visible to either of my cable modems (a D-Link DCM202 and a Motorola SB6121).

Now I am going to have to do some investigating to find out why the ZyXEL GS105S works without its MAC address gumming up the works. And I also will to try to find out if it has any accessible ports. I did not initially do any kind of PEN testing on that switch because I thought it was a simple layer 2 device (I didn't even notice that ZyXEL had assigned it a MAC address until I read your post).
--
Some days you're the dog; some days you're the hydrant.

FirebirdTN

join:2012-12-13
Brighton, TN
kudos:1

FWIW, mine is a GS-105B.

-Alan