[TelstraClear] DHCP setting question

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Rickles

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#65803 6-Aug-2010 18:24

Hi, I have been running TelstraClear cable internet for a couple of weeks now and decided to instal my wifi router.

Apart from the usual rigmarole of setting the IP and DNS settings using a laptop, turning these off on the desktop, etc etc, it all works perfectly fine.

However, as expected to get things rolling I also had to turn off DHCP in the TCL modem and turn on DHCP in the router .... BUT the DHCP setting in the TCL modem has come back on.

Is this usual and/or likely to cause problems?

I confirm that internet access via desktop and laptop using ethernet is fine, as is wifi access using the laptop.

Thanks,

Ricky.

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#364520 7-Aug-2010 00:32

Are you talking about the Motorola SB5101 TCL cable modem?

Of so, it doesn't have a DHCP server - any DHCP service will relate to a client service that it will need to be on for it to connect WAN-side (upstream). The lack of DHCP server is why you would have needed to have any directly connected PC set up with a fixed IP and the DNS refs before you introduced your own router, which now takes care of that.

Or I may have misunderstood your question

sbiddle

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#364557 7-Aug-2010 08:27

Nothing needs to be changed in your modem. The DHCP setting does nothing as the modem is only acting as a bridge.

Rickles

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#364578 7-Aug-2010 09:42

Ian and Steve,

Thanks for your replies.

Ian: Yes, the Motorola SB5101. Sorry, but the rest of your explanation I do not understand.

Steve: I appreciate that the modem is essentially a 'bridge', but it's own DHCP statement, particularly the second sentence, is confusing, and I quote ...
"DHCP Server Enabled
The SURFboard cable modem can be used as a gateway to the Internet by a maximum of 32 users on a Local Area Network (LAN). When the Cable Modem is disconnected from the Internet, users on the LAN can be dynamically assigned IP Addresses by the Cable Modem DHCP Server."

Does that mean the modem can act as a DHCP server for networked computers in instances where a basic router or switch is used to connect them all, regardless of any live internet connection?

R.

sbiddle

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#364581 7-Aug-2010 09:54

Just for clarification the DHCP setting is not a replacement for a router with DHCP. It's for diagnostic tsting only.

When the cable modem boots up if it's unable to connect to the CMTS it can allocate an IP to a local PC so that the cable modem diagnostic page can be accessed. This saves the end user having to manually change their IP to something on the 192.168.100.0/24 range so that they can access the web page.

There is nothing in the cable modem setting that should be changed by an end user.

Rickles

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#364582 7-Aug-2010 09:58

S,

That makes sense ... thanks for your answer.

R.

sbiddle

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#364585 7-Aug-2010 10:09

There is no need to touch this setting since your router (or any other device) sits behind the cable modem with it's own static IP in bridge mode.

Rickles

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#364611 7-Aug-2010 12:05

Yup, got it.

As a matter of interest, does TelstraClear use/check on the MAC addresses?

When setting up the wifi router I used the desktop's MAC, but the system seems to work regardless of what that setting is.

R.

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louisgoodier

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#364615 7-Aug-2010 12:23

@Rickles

MAC Addresses of your local machine are used for internal communication on the network. When the router forwards the packets on it applies its own MAC address.

Rickles

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#364642 7-Aug-2010 13:29

What I was asking is, does TelstraClear require MAC as a form of authentication?

R.

sbiddle

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#364644 7-Aug-2010 13:37

Rickles: What I was asking is, does TelstraClear require MAC as a form of authentication?

R.

Yes and no. Your IP address is tied to the MAC address of your cable modem. There is no need for you to use any form of MAC authenticatin.

The only thing you need to enter is your IP, gateway, natmask and DNS servers in your router.

Rickles

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#364648 7-Aug-2010 13:59

Hmmm, OK.

Using the cable modem MAC the system don't work.

Using either the desktop MAC or the wifi router MAC, internet access is fine and dandy in both instances.

I've read that where MAC authentication is used by the ISP, then one should set the router to 'clone' or mimic the desktop/primary computer's MAC.

Is it better to use one or the other MAC address?

R.

sbiddle

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#364657 7-Aug-2010 14:25

There is no need at all to be playing with MAC address or anything else in your router. As I explained above you only need 4 settings in your router to make things work.

Messing with things like MAC addresses will break things especially if you have no idea what you are doing. You typically can't have two devices on a network with the same MAC which is exactly what you're trying to do, hence the reason it won't work.

Just stick with the settings you need to enter and leave the rest - if you keep fiddling with things that you obviously don't understand you will never get what is a very basic setup working.

Rickles

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#364664 7-Aug-2010 14:42

Lesson noted .

Sorry for asking, just trying to learn.

R.

louisgoodier

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#364770 7-Aug-2010 18:30

There are some ISP's that require a MAC clone on the router for authentication, the router simply uses its own MAC internally and whatever computer in the network you decide to mimic as the clone. Typically - this never needs to be touched and only complicates the process and ISP's don't use it anymore.

Telstra use PPPoe
Telecom use PPPoA

both VC MUX and LLC will work with both, and the MTU value can be set to 1454. The next router will fragment the package if required by the ISP.

Enjoy.

sbiddle

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#364782 7-Aug-2010 18:51

louisgoodier: There are some ISP's that require a MAC clone on the router for authentication, the router simply uses its own MAC internally and whatever computer in the network you decide to mimic as the clone. Typically - this never needs to be touched and only complicates the process and ISP's don't use it anymore.

Telstra use PPPoe
Telecom use PPPoA

both VC MUX and LLC will work with both, and the MTU value can be set to 1454. The next router will fragment the package if required by the ISP.

Enjoy.

Just FYI these do not apply as it's a TCL cable connection, not ADSL.

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