# FreeBSD Box before ISP Modem



## Jack R (Mar 23, 2017)

Hi

My ISP uses coaxial for internet. Right now, coaxial cable from ISP is connected to this modem and CAT-5 is connected to FreeBSD box that I have. What I would like to do is to have my FreeBSD box before my modem,


```
-----> Coaxial Cable
=====> CAT-5

Internet from ISP -----> FreeBSD Box -----> Modem =====> Router =====> Switch

[B]NOTE:[/B] Modem is just a modem, and it is [B]not[/B] Modem+Switch+Router+Wifi combo.
```

Is it possible to do this? If so,

What do I need to know and look at in order to configure and setup my FreeBSD box?
My box has PCI Slot, what card do I need to buy to perform this task?

Thank you,


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## SirDice (Mar 23, 2017)

You still need a modem to convert the coaxial (DOCSIS?) signal into something FreeBSD understands and then convert it back to DOCSIS for the modem. Why would you want to do that?

If you have a decent modem, put it in bridge mode.


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## usdmatt (Mar 23, 2017)

If it's really just a modem then you should be initiating the Internet connection from FreeBSD. (In my case in the UK I have a PPPoE client set up on my router and my modem is basically just an ADSL -> Ethernet converter). If the "Modem" is logging into the ISP and providing you a private network on the Ethernet then it's a router.

Your diagram doesn't make much sense. You can't have the modem connected straight to a switch, unless it is actually is a router. Personally I'd be far happier using a modem that gives me proper Ethernet into my server than trying to mess about with a Coax connection in FreeBSD.


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## Jack R (Mar 23, 2017)

usdmatt thanks for your reply. I updated my original post, I don't know why I push switch instead of router in my diagram.

SirDice thanks for your respond, the reason I was thinking to have my FreeBSD box before my modem is to protecting it (my modem has some web server running internally with no way of protecting it with username and password). That FreeBSD box is just act as Firewall.

My modem is only a modem, one coaxial input and one CAT-5 output. usdmatt how do I know what kind of communication my ISP uses?


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## SirDice (Mar 23, 2017)

Jack R said:


> SirDice thanks for your respond, the reason I was thinking to have my FreeBSD box before my modem is to protecting it (my modem has some web server running internally with no way of protecting it with username and password). That FreeBSD box is just act as Firewall.


These configuration web GUIs are typically only accessible from the _inside_, not the outside.


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## Eric A. Borisch (Mar 23, 2017)

Jack R said:


> SirDice thanks for your respond, the reason I was thinking to have my FreeBSD box before my modem is to protecting it (my modem has some web server running internally with no way of protecting it with username and password). That FreeBSD box is just act as Firewall.



I leave the modem outside the firewall and treat it as untrustworthy as the rest of the outside world. Why would you want to add an additional (and potentially not configurable by you) device inside your firewall?

Not to mention that I've never seen or heard of a consumer-end PCIe DOCSIS -- the standard used for cable modems -- card. And even if someone makes one, you would now have a potentially breachable subsystem sitting on the PCIe bus of your firewall.


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## Jack R (Mar 23, 2017)

Thank you all


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