# Is MOCA causing my network issues?



## magic168 (May 9, 2009)

Really weird issues, and I'm trying to figure out if the MOCA network is causing it.

Just recently (no changes to the network setup/topology), my computer and other devices started getting 176.16.x.x IP's when my router's DHCP IP range is in 192.168.x.x land. I was really confused and couldn't find the cause. Thinking my router just went nuts, I did a factory reset and I thought all was fine.

Unfortunately not...I looked at the logs of my router, and it's still getting DHCP requests from MAC addresses that I don't recognize in the 176 IP range. And on my Windows desktop, I can see other machines/media servers on my network that are definitely NOT mine!

So, the only thing I can think of is the MOCA network. I don't have a POE filter anywhere installed (and I'm actually not quite sure where I should place it...)

I have two cable outlets in my place. One is split: one end goes to the Actiontec MOCA adapter, other end goes to my Motorola cable modem. The actiontec is on my router by ethernet. The other outlet is pretty simple -- goes directly to my Tivo Roamio Plus.

1) Is the MOCA network allowing my network to comingle with other networks (including one with a conflicting DHCP server?) While I knew there was a chance my info could "leak" outside without a filter, I wasn't aware multiple networks could coexist through MOCA? 

2) If indeed it is, where would I place POE filters? I can't reach/ don't have access to the entry point -- do I place a filter before the splitter and then leave the Roamio line alone? Or do I place one before the splitter AND one before the Roamio?

Thanks, and apologies for the long post...I am not a network newbie (though certainly not an expert) and this has gotten me stumped for a few days now...


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## BigJimOutlaw (Mar 21, 2004)

1. You can disable the moca network and find out. Don't know what's going on there.

2. The POE filter goes on the INPUT socket of your main splitter. Putting it on the modem/adapter's leg or on the Roamio's leg would block the signal.


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## fcfc2 (Feb 19, 2015)

Hi,
You must have missed reading up on MoCA. Assuming you are not on Fios, immediately if not sooner, I would suggest you contact your cable company and see if you can get a MoCA POE (Point Of Entry) filter installed, or order one or 2 off of Ebay, which is the cheapest source. MoCA POE filters and Whole Home DVR filters are functionally the same and either should be placed on the "input" of the first splitter in/outside your home. If you are in a single family home, there is usually a plastic box outside where the main line is split, this is the location to place the filter. If you live in an apartment or condo there may be a central "closet" which is locked. If that is your situation, get in contact with the cable company and request they install one of their filters for you. Right now, it sounds like you and a neighbor may be sharing each others networks....do you do any banking online????


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## Time_Lord (Jun 4, 2012)

I'd be curious to know what the first 6 bytes of the mac address are, from there you can determine and the manufacturer is.

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## mulscully (May 31, 2003)

fcfc2 said:


> Hi,
> You must have missed reading up on MoCA. Assuming you are not on Fios, immediately if not sooner,


So if someone has FIOS they don't have to worry about a POE filter? correct?


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## fcfc2 (Feb 19, 2015)

mulscully said:


> So if someone has FIOS they don't have to worry about a POE filter? correct?


Hi, You don't need a POE/ Whole Home Dvr filter on a Fios system because they use an ONT / optical network terminal, where the MoCA Lan frequencies are stopped. In theory, there might be some benefit from using a filter, because of the "reflective" quality of a filter, it might "strengthen" the MoCA signal, but it is definitely not necessary.


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## magic168 (May 9, 2009)

OK, I've attached a quick PDF mockup of my pretty simple setup. I know the ideal place to put a filter is before the splitter on the roof/box/etc before it enters my house, but I really have no way to access that.

So my question is, where are the place(s) I *need* a MOCA filter (without killing the network?

Is it just (1)? Or (1) and (3)? Or can I do (2) and (3)?

Thanks!


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## BigJimOutlaw (Mar 21, 2004)

The only place it will work is on the input side of the roof splitter.

Anyplace else blocks the moca signal between the adapter and Tivo.


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## fcfc2 (Feb 19, 2015)

magic168 said:


> OK, I've attached a quick PDF mockup of my pretty simple setup. I know the ideal place to put a filter is before the splitter on the roof/box/etc before it enters my house, but I really have no way to access that.
> 
> So my question is, where are the place(s) I *need* a MOCA filter (without killing the network?
> 
> ...


Hi,
Big Jim called it, but if you were on an Xfinity system which uses MoCA with Comcast, they might have a POE filter already installed at the drop. I would just call Comcast and tell them that you are using MoCA and don't want to cause any problems. They will install a filter where ever necessary, they may or may not charge you, but then you will know it's done right.


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## Jonathan_S (Oct 23, 2001)

magic168 said:


> OK, I've attached a quick PDF mockup of my pretty simple setup. I know the ideal place to put a filter is before the splitter on the roof/box/etc before it enters my house, but I really have no way to access that.
> 
> So my question is, where are the place(s) I *need* a MOCA filter (without killing the network?
> 
> ...


[inlined the attached image]
How is the Roamio networked to the cable router? Is it Ethernet or MoCA?

A filter placed at (1) or (3) looks like it would block the Roamio from receiving MoCA signals from the cable modem/router. A filter at (2) would only block that unlabeled box from MoCA, but I'm guessing the red dotted line means it's connected via Ethernet and so it's ignoring MoCA anyway.

If I'm reading your diagram correctly, the only place the coax to the Roamio meets the coax near the router is at that external, inaccessible splitter. So any filter downstream of that splitter would block the MoCAs path throughout your house...


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## magic168 (May 9, 2009)

Jonathan_S said:


> [inlined the attached image]
> How is the Roamio networked to the cable router? Is it Ethernet or MoCA?
> 
> A filter placed at (1) or (3) looks like it would block the Roamio from receiving MoCA signals from the cable modem/router. A filter at (2) would only block that unlabeled box from MoCA, but I'm guessing the red dotted line means it's connected via Ethernet and so it's ignoring MoCA anyway.
> ...


What is the "cable router?" If you mean the external splitter, there is just a coax line that comes in from my wall in the living room. Same thing for the basement...

If you mean my internet router, the MOCA network takes care of that connection...it connects to my Actiontec, which is connected to the internet router via Ethernet.


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## Jonathan_S (Oct 23, 2001)

magic168 said:


> What is the "cable router?" If you mean the external splitter, there is just a coax line that comes in from my wall in the living room. Same thing for the basement...
> 
> If you mean my internet router, the MOCA network takes care of that connection...it connects to my Actiontec, which is connected to the internet router via Ethernet.


I said "cable modem/router" because I wasn't sure which of the two devices you had pictured there was creating the MoCA network (or if there was some 3rd device making an Enternet to MoCA bridge).

Basically I don't feel I've got a good handle on which bits of your network are Ethernet, which are MoCA, how they all connect to each other. So it's a little hard to give exact guidance. But if you insert a point of entry MoCA filter such that it interupts the only coax path between a pair of MoCa devices those two devices will stop being able to communicate to each other.

Based on that drawing it _looks_ like your inaccessable splitter is a key part of the coax link between various MoCA devices in your house - so any point of entry filter placed on an output of that looks to break your MoCA network.


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## magic168 (May 9, 2009)

Well, I guess I will retire my MOCA network even though it's worked well and instead try to use my semi-unstable wifi for now...Comcast wants to charge me to get a POE filter installed.


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## dianebrat (Jul 6, 2002)

magic168 said:


> Well, I guess I will retire my MOCA network even though it's worked well and instead try to use my semi-unstable wifi for now...Comcast wants to charge me to get a POE filter installed.


...and you can't install the POE filter yourself because? is it really totally and completely inaccessible? you just need to get it before the first splitter, it's a 2 second job on the input line to the house/apt.

And don't discount powerline networking, I would use that over wifi in almost all cases.


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## krkaufman (Nov 25, 2003)

magic168 said:


> Well, I guess I will retire my MOCA network even though it's worked well and instead try to use my semi-unstable wifi for now...Comcast wants to charge me to get a POE filter installed.


How much? The MoCA filters can be had for $8 or less.

One alternative I've pondered is calling Comcast to upgrade to their X1 services including the X1 DVR, so long as they provide free installation with a money back guarantee, and then cancelling the service within the free refund window. The benefit being that the X1 DVR communicates over MoCA, so a MoCA PoE filter and MoCA validation of the home coax plant would be part of the X1 installation.

Another alternative that might get Comcast's attention is to use that MoCA adapter to create a MoCA network, but don't have the Ethernet port connected to your home LAN. Instead, maybe connect it to some old PC/laptop you have sitting around (that doesn't contain any personal data) and see if the computer can get any Internet connectivity. Heck, just let it keep trying to hunt for a DHCP server; that might be enough to get their connection to your home properly configured.

A third option might be to file an FCC complaint, detailing how Comcast's refusal to install a MoCA PoE filter is leaving your home network insecure.


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## krkaufman (Nov 25, 2003)

Jonathan_S said:


> I said "cable modem/router" because I wasn't sure which of the two devices you had pictured there was creating the MoCA network (or if there was some 3rd device making an Enternet to MoCA bridge).
> 
> Basically I don't feel I've got a good handle on which bits of your network are Ethernet, which are MoCA, how they all connect to each other. So it's a little hard to give exact guidance. But if you insert a point of entry MoCA filter such that it interupts the only coax path between a pair of MoCa devices those two devices will stop being able to communicate to each other.
> 
> Based on that drawing it _looks_ like your inaccessable splitter is a key part of the coax link between various MoCA devices in your house - so any point of entry filter placed on an output of that looks to break your MoCA network.


I had a minute (and wanted some practice), so figured I'd add some add'l annotation to the OP's diagram (see below).

*NOTES:*

MoCA PoE filter needed at location *(4)* -- or somewhere between *(4)* and where the coax line connects to the rest of Comcastia.

The MoCA network is being created by the MoCA adapter at the bottom of the drawing, at location *(9)*, via the adapter's connections to both the coax plant and the router's Ethernet LAN ports. (Note that a simple cable modem such as that pictured in the diagram, distinct from a multi-function gateway, could never be used to create a MoCA network, as such a modem would lack connectivity to the home's Ethernet network, the LAN side of the router/gateway.)

Depending on the model and features of the cable modem, a MoCA filter _may be needed_ at *(8)* or *(7)*, on the input to cable modem. (Many modern modems, such as SB6141, have a built-in MoCA filter.)

As an aside, the splitter in the basement may not be necessary if the modem is connected through the MoCA adapter's coax out port (see it) -- though many prefer the OP's configuration, so as to remove any concerns with pass-through interference. In the pass-through configuration, an additional MoCA filter would not be needed for the cable modem, regardless of its model, as the MoCA adapter, itself, would be filtering any MoCA frequencies from its coax out port.


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## magic168 (May 9, 2009)

krkaufman said:


> I had a minute (and wanted some practice), so figured I'd add some add'l annotation to the OP's diagram (see below).
> 
> *NOTES:*
> 
> ...


Comcast started off saying it'd cost $60 for a tech to come out and install it. I complained a bit and they said since I'm a loyal customer, they'd cut it down to $50. I told them that's still ridiculous and called back and spoke to another person and they just scheduled someone to come out for free.

Funny thing is, I chatted with a Comcast tech who was on my block earlier and he first thought I was just asking for a filter, which he volunteered easily, then even volunteered to come install it if the box were easily accessible. Unfortunately, since it's either on the roof or on a pole, he had to have a work order...


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## krkaufman (Nov 25, 2003)

magic168 said:


> Comcast started off saying it'd cost $60 for a tech to come out and install it. I complained a bit and they said since I'm a loyal customer, they'd cut it down to $50. I told them that's still ridiculous and called back and spoke to another person and they just scheduled someone to come out for free.
> 
> Funny thing is, I chatted with a Comcast tech who was on my block earlier and he first thought I was just asking for a filter, which he volunteered easily, then even volunteered to come install it if the box were easily accessible. Unfortunately, since it's either on the roof or on a pole, he had to have a work order...


Heh, I was going to add "keep your eyes out for a Comcast tech in your neighborhood" as another option, but figured they wouldn't be able to do more than give you a freebie MoCA filter for a self-install.

Very glad to hear Comcast is going to help you out, following their usual level of resistance. (When it comes to Comcast growing their profits, resistance is fertile! oof!)

Let us know how it works out...

edit: p.s. What're you using for network diagramming?


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## magic168 (May 9, 2009)

Will update this thread after they install next Wednesday. 

The "network diagram" was just done in powerpoint.  No special tool.


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## krkaufman (Nov 25, 2003)

magic168 said:


> Will update this thread after they install next Wednesday.
> 
> The "network diagram" was just done in powerpoint.  No special tool.


Heh, I tweaked it in Paint Shop Pro -- thus the curiosity regarding better diagramming tools. Thanks for the feedback.

p.s. Good luck...! Oh, and before Comcast arrives, check your modem's product documentation to determine whether it has a built-in MoCA filter; if not, see if your Comcast tech will gift you a MoCA filter, in case you later decide/learn you need one for the modem.


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## JARON46 (Jun 8, 2011)

Could you abandon the coax going to your Roamio and replace the 2 way in your basement with a 3 way splitter and run a new coax wire from basement to Roamio.

You could then put the POE filter at the in of the new 3 way splitter


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## magic168 (May 9, 2009)

COmcast just came and went. THey installed a POE filter in front of the splitter going into the lines into my house and...network dead. THe guy realized I was doing a Tivo and not a Comcast DVR and started saying the Tivo filters are different...so I whipped out the one I bought from Amazon. He was nice and installed it and bam, network dead again.  He removed the filter and the MOCA network is live again. And now he left...and I still have no viable solution.


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## magic168 (May 9, 2009)

So can someone shed some light on what exactly is going "through" the MOCA network? So only the Tivo is using the MOCA network...and now I've turned on encryption on the Actiontec adapter. What can people access theoretically? The MOCA adapter is behind my router, not directly connected to a split line. All the internet traffic should still be going through my router/cable modem, right? What is the security risk?


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## JARON46 (Jun 8, 2011)

I had to isolate my modem from the moca network. The modem constantly rebooted.

I split my cable where it entered basement and ran coax to modem.

Other wire added 3 way splitter with POE filter on "in" of 3 way splitter.

Ran coax to Roamio and 2 mini's.

You might try POE filter on modem to isolate it from moca.


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## Jonathan_S (Oct 23, 2001)

magic168 said:


> COmcast just came and went. THey installed a POE filter in front of the splitter going into the lines into my house and...network dead. THe guy realized I was doing a Tivo and not a Comcast DVR and started saying the Tivo filters are different...so I whipped out the one I bought from Amazon. He was nice and installed it and bam, network dead again.  He removed the filter and the MOCA network is live again. And now he left...and I still have no viable solution.


Hmm. That's acting like there's another splitter closer to the cable company that the TiVo's coax is connected to... But I'd imagine that the Comcast guy would have noticed that.

It he was still there you could have tested temporarily disconnecting the outputs of the splitter to confirm that the TiVo was connected off one leg and the cable modem and MoCA adaptor were connected off the other.

But now I'm kind of at a loss for how to further remotely troubleshoot this.


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## fcfc2 (Feb 19, 2015)

magic168 said:


> So can someone shed some light on what exactly is going "through" the MOCA network? So only the Tivo is using the MOCA network...and now I've turned on encryption on the Actiontec adapter. What can people access theoretically? The MOCA adapter is behind my router, not directly connected to a split line. All the internet traffic should still be going through my router/cable modem, right? What is the security risk?


Hi,
An important question or two, when you say your network is dead, are you really saying you lost "internet" service? What is the make and model # of your cable modem? Assuming both you and the cable tech have a MoCA filter, I think I might have an explanation for what otherwise is a total mystery.
What MoCA actually does is "piggyback" over the same coax cables that are used for your internet and TV service but at higher frequencies. The internet service and TV service uses the lowest frequencies usually from 5-850MHz. Cable MoCA uses frequencies from about 1125-1675MHz to transfer data from both the internet and your local network back and forth. MoCA devices are relatively powerful to overcome the loss from poor cabling /splitters, and multiple splitter installations. The most readily available MoCA POE or Whole Home DVR filters both block and "reflect back" signals in the 1125-1525MHz range. The "reflective" quality of the filters which make the MoCA signal "stronger" can cause significant interference in the lower frequencies and can either disrupt various cable TV channels and the frequencies used by the cable modem for internet service.
I am guessing that when the MoCA filter was installed, it boosted the MoCA frequencies enough to interfere with your internet service / signal. This is not an uncommon problem. Some cable modem manufactures have adapted by building in a MoCA filtering circuit. If the filter is not builtin, a troubleshooting step would be to either install another filter on the input to cable modem and / or use a Sat grade diplexer with the upper Satellite port going to the MoCA cabling and the Antenna port going to the cable modem.
Something similar to this is the only possible explanation for what you are describing. 
Regarding the issue of security. If you have enabled encryption on your MoCA devices, you are probably safe. The MoCA signals are strong but they are not unlimited in terms of range. If you are in a single family home the MoCA signal is probably limited in range to one or two neighbors, however in a more dense housing situation, i.e., apartments and condos, the number of possible guests increases. Anyone with a MoCA adapter within range has the same access to your network as you do. The other issue besides your security is that the same MoCA can cause interference on the cable companies equipment and disrupt your neighbors TV or internet service.


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## mister_e_man (Aug 31, 2015)

I had a conflict between the FIOS moca and the one in theTiVo. Turned out there were two problems. First, I needed to rely on the FIOS Moca and turn off the TiVo one. Then I needed to have FIOS gateway support turn off some sort of filtering that was blocking the ability of the Tivo to use the FIOS mocanet. 


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