How do I set up ethernet network having attached a MoCA adaptor from cable inlet into modem? It seems I need a "self assigned IP"?

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Level 1

13 points

How do I set up ethernet network having attached a MoCA adaptor from cable inlet into modem? It seems I need a "self assigned IP"?

I live in an old apartment building with very thick walls, and have a miserably spotty wireless network. In hopes of creating an undisturbed ethernet network for my computer and various other gadgets, I purchased two ActionTec Moca adapters, and set it up as suggested in a helpful review on Amazon: put one MOCA adapter "upstream" to the cable modem. The incoming coax with the Internet signal would plug into the MOCA "in" port then the MOCA's "out" coax goes into the coax on the cable modem. Then the LAN port on this MOCA goes into a LAN port on the switch/router. The Ethernet port on the modem goes into the WAN port on the same router. This "triangle" of connections is confusing to someone who is not networking savvy because they assume that all network connections have to be linear." The adaptors light up as they are meant to, indicating that the signal is there, and my iMac tells me thatDiagnostics window tells me that the internet connection appears to be working correctly." Only the little button in the Network Diagnostics panel next to 'Network Settings" is yellow. When I run the Setup Assistant, it says that "You cannot connect to ISP automatically, so you need to enter information to set up your connection. Selec the appropriate item then enter the required information. If you don't kow the infromation, contact your ISP." I checked "I have a DHCP Client ID and entered my IP address as copied from the network panel. It said congratulations you are now connected to the internet!" But then no browser window window would open, and Safari said "you are no longer connected to the internet". What did I do wrong?

Mac OS X (10.6.4)

Posted on Jan 27, 2014 11:42 AM

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Answer 1

baltwo

Level 9

62,362 points

Jan 27, 2014 1:05 PM in response to Sprucewein

Not sure you contacted your ISP, but System Preferences->Network->Internet and set things up as the ISP tells you. Then, check the Advanced settings button. While in System Preferences, check Help->System Prefs help->search for network and check the various articles.

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Answer 2

Jan 27, 2014 2:07 PM in response to Sprucewein

The advice you got from Amazon sounds like nonsense to me (though I'm not familiar with the specific equipment). I can't see why you would need two connections between the cable modem and the router. I would have exepected that you would would simply connect the output ethernet port to the WAN port on the router and your Mac to one of the router's LAN ports.

I would expect the LAN ports on the cable modem to be a router output so that more than one device can be connected without an additional router.

In all this, only one device should be acting as a DHCP server and issuing IP numbers, presumably the second cable modem. Anything else must be set to passthrough, or bridge mode, or whatever they call it. If you have more than one device issuing IP numbers the result will be chaos.

Not clear what the first MOCA is there for anyway... but only one DHCP server is always the rule no matter how you have it configured.

(For example, I have a cable modem which issues the IP numbers: a line is connected from one of its ethernet outputs which goes to an Airport Extreme to which several devices are connected both by ethernet and wireless; another line from the cable modem goes to a network switch to which several devices at the other end of the room are connected; and sometimes I connect an Airport Express to the Airport Extreme to provide a separate wireless network for a guest - this is not hidden where the other wireless network is hidden. Only the cable modem issues IP numbers; all the rest pass these issued numbers through onto the connected devices.)

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Answer 3

baltwo

Level 9

62,362 points

Jan 27, 2014 2:16 PM in response to Roger Wilmut1

Thanks for popping in. FWIW, my Motorola SB6121 Surfboard modem only has one ethernet outlet, which goes to a router, serving two iMacs.

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Answer 4

Jan 27, 2014 2:40 PM in response to baltwo

Some cable modems - the first one I had, for example - have just the one output so you have to use a router to connect more than one Mac; my present one has four outputs.

The 'only one DHCP server' rule is vital. As soon as you get two devices issuing IP numbers you are asking for a clash where between them they issue the same number to different machines, and then the whole thing falls over.

In my original setup the modem simply passed through the IP number set by my ISP, so that became the router's IP on the internet, and it then issued local IPs such as 192:xxx:xxx:xxx. With the second modem, it took the WAN IP number and could be set either to issue local IP numbers or pass the WAN number through to a router - I took the first option (so that I could use its outputs as well as the Airport) and the Airport is set to 'bridge mode' and doesn't issue IP numbers.

It sounds to me as if the OP has got two or even three devices issuing IP numbers, which would certainly cause trouble.

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Answer 5

Jan 27, 2014 2:54 PM in response to Roger Wilmut1

Incidentally the 'self assigned IP' message is the computer telling you that it's been unable to obtain an IP number from the router, and so has assigned itself one as an emergency measure - just so that it has one, you can't connect to anything with it because nothing else knows what it is.

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Answer 6

Sprucewein Author

Level 1

13 points

Feb 6, 2014 5:19 AM in response to Roger Wilmut1

Thanks so much for your thoughts and suggestions! If you are willing to ponder more:

The function of the MoCA adaptors, as I underrstand it, is to send the Internet signal over all the coax cable that already exists in most buildings, to obviate the need to install Ethernet wiring inside the walls of a home. These adaptors take the signal that is coming in from the ISP and send it back out into all the other coax already installed in the home. The friend who told me about them uses a PC. She set up two adaptors as instructed on the Amazon page, one at the input site upstream of her modem, and the other at the end of a coax cable in another room, and then into the Ethernet port of her computer or other device, and voila - she had an Ethernet network running through the coax cabling which already exists in her home.Here's where my technical understand begins to be muddy: the adapters "double back" the signal from the modem back through the coax cable network. On the website at Amazon, this seems to be the experience (ie plug and play) of most of the purchasers of these adaptors. I'm still in a muddle tho, about how to establish the proper IP address for my desktop Mac in another room, when connected by ethernet cable to the adaptor, into the coax cable. The lights on it indicate the signal is there, but what should my computer's IP address be, and must it derive from the Airport Extreme? the "trianle" of connection described by the usser on Amazon makes me think that that connection should establish the address that the AE created, but apparently not...

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Answer 7

Feb 6, 2014 5:35 AM in response to Sprucewein

I wouldn't expect the oMoCa adaptors to issue IP numbers, simply act as a passthrough to get the connection to the modem. It's not clear how you've got this set up or how the Airport comes into it.

From what you say the modem has several ethernet outputs - is this correct? - then you are directly connect to it by cable; and possibly an Airport Extreme is also connected to it.

Unless you are connected to the Airport either by cable or wireless it doesn't come into your own connection, though other computers may be connected through it.

If all this is as I described the modem must issue the IP numers and the Airport must have 'Connection sharing' in the 'Internet' section (after clicking 'Manual setup) set to 'Off (bridge mode)'. Then it simply passes the IP numbers issued by the modem through to any computers connected through it.

If the modem has only one ethernet output socket then it will be connected to a router (either the Airport or something else) through which everything else is connected, and that router should be set to issue the IP numbers as the modem will simply pass through the IP number issued by the ISP.

Whatever set up you have, you can only have one device issuing IP numbers or problems will result.

Your own Mac should be set to 'obtain an IP number automatically' or 'Use DHCP' (the same thing, and don't use 'DHCP with manual address). The number you are issued with will be in the 'local use' range, probably beginning with 192, and is not the same as the IP number seen by the outside world.

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