networking Question on connecting device(s) directly into a Modem

[NaviOlly]

Hello,

 

I have a question regarding multiple Ethernet ports on my modem.

 

So I recently upgraded my internet to Gigabit Plan with Xfinity and picked up myself a new modem. (NETGEAR Nighthawk Cable Modem CM1200)

 

Normally all the modems I have used, all have one Ethernet Plug on the back, to connect to a Router. However, Nighthhawk CM1200 has four available connection in the back. What I want to know if it is alright to connect few of my devices straight into the modem. Are there any pros and cons? Such as security issues?

 

I did trying googling around but could not get any good answers. I have also asked some of my friends and IT Specialists at my job but none were able to provide me with good answers.

 

Thanks for reading and perhaps helping me understand 

 

***If it matters

***Router: Nighthawk X6 R7900

[Enderman]

https://www.netgear.com/home/products/networking/cable-modems-routers/cm1200.aspx

"M1200 supports up to four (4) public IP addresses (WAN IP) with a Comcast Business account. Multi-IP address** support for up to four home networks allows for multiple servers to run at the same time. "

 

Just like having four different modems.

You don't need routers, those are just for wifi or for acting as a switch for multiple devices.

Nothing wrong with plugging a computer straight into the modem, as shown in the images on the page.

[Alex Atkin UK]

As mentioned, your ISP would need to support issuing you more than one IP address at the same time which is likely not going to be the case if its a residential connection, at least not without an additional fee.

 

Its definitely less secure though, as any issue with your devices firewall and a hacker can get straight in, whereas normally they would have to compromise the router first.  But its certainly less of a headache (or security risk due to how locked down they are) if you connect games consoles that way and play online games.

 

There's also the fact you can run QoS if you go via the router, although that's both less likely to be needed on Gigabit plus its less likely your router is powerful enough to handle it anyway.

[Donut417]

To add in to what @Alex Atkin UK has stated, Comcast will have issued the proper firmware as well. Many D3.1 modems have multiple Ethernet ports, for Link aggregation, so you can get faster than 1 Gbps. Im not sure if Comcast has issued the correct firmware for that device yet. I know that most of the modems, this feature was not implemented at the time of launch. Though I have heard that some modems have the proper firmware and people are getting the full 1 Gbps, maybe a little more. Most of the time the Gigabit teir tops out at like 950 Mbps. 

 

Further more you can check your local rate card for the cost of additional IP's. Or at least see if thats an option, because not all areas can get multiple IP's on a residential connection. 

[NaviOlly]

Thank you everyone for all the insight! Has been a learning experience for me. (A side of networking that I never really thought about)

[Alex Atkin UK]

On 6/23/2019 at 3:53 PM, Donut417 said:

To add in to what @Alex Atkin UK has stated, Comcast will have issued the proper firmware as well. Many D3.1 modems have multiple Ethernet ports, for Link aggregation, so you can get faster than 1 Gbps. Im not sure if Comcast has issued the correct firmware for that device yet. I know that most of the modems, this feature was not implemented at the time of launch. Though I have heard that some modems have the proper firmware and people are getting the full 1 Gbps, maybe a little more. Most of the time the Gigabit teir tops out at like 950 Mbps. 

 

Further more you can check your local rate card for the cost of additional IP's. Or at least see if thats an option, because not all areas can get multiple IP's on a residential connection. 

I don't even want to think about link aggregation.  I tried to do it between my server/NAS and Switch, was a complete and utter failure.  Just ended up getting half the bandwidth down each connection with tons of packet loss, presumably due to out-of-order packets.  Its a nightmare I hope I never have to look into again.