Virgin Hub and Managed Switch

[fishkake]

Hi there

Apologies if I'm re-asking an existing question. I can't possibly be the first to ask, but I've been googling and can't find an answer, possibly because I don't understand the terminology correctly.

I have a Virgin Media Superhub 2 which I want to use in modem mode, and I'm simply asking the best way to do this with multiple hardware. I have a Cisco SG300-10P managed switch and a Cisco 1242AG access point, and ideally I'd like to create a wired and wireless network with these components.

I also have a bunch of cheap switches, a Cisco 1100 AP, a D-link DIR-300 wireless router and plenty of laptops etc which could become linux routers etc if need be, but I was hoping to accomplish my aims with the Virgin hub (in "modem mode"), the cisco managed switch and a wireless AP.

It is possible that the question I'm really asking is "do I need a router?" - in which case could the DIR-300 or a linux laptop perform this task adequately?

I'm that dangerous kind of techie - the kind who knows enough to think he knows everything, but not enough to do anything right. Any help is hugely appreciated!

 

[bill001g]

I suspect your switches even if they are managed are stupid. Even if you were to have very advanced full layer 3 switches you would still need a router.

Even though technically a layer3 switch is router the key function it does not have is NAT. Layer3 switches are designed to be fast and not delay data at all. Anything that must modify the packet is not supported because it will delay the data. This means NAT and VPN are not supported by any layer3 switch.

This is the key difference between what is a router and a layer3 switch.

Still I suspect you switches are only layer2 and pretty much that means they support vlans and some of the simpler features. Your new problem is that most consumer routers are really stupid....they are actually better called gateways because they do not support many feature a true router has.

You need device that supports more than a single lan subnet and best if it support vlan tagging. You could use a pc with 2 nics and build your own firewall/router with many free open source router software. PFSENSE is one of the more common firewalls people run but there are many.

 

[jsmithepa]

It is possible that the question I'm really asking is "do I need a router?"

If by router you mean a NAT device, the answer is yes. Something needs to do NAT between the Internet and your LAN.

Switches typically don't do NAT. A Wifi router does and as long it got the bandwidth needed you can insert it right after the modem.

Managed switches need configuration, oftentimes beyond the capability of a home user, they are not plug&play.

 

[fishkake]

So it seems NAT is the thing I need to look in to.

I now have more questions, like how to build a router like PFSENSE, exactly how Virgin's "Modem mode" works, and how to do NAT to a variety of different inbound servers through a domain I just bought. But those are questions for anther post or forum.

Thanks both of you for your help! 🙂

 

[fishkake]

FYI anybody else who finds this post: http://serverfault.com/questions/738175/can-a-cisco-sg300-layer-3-switch-act-as-a-nat-router

Basically, the answer is no. This link also suggests PFSENSE.

Nothing against the above answers, but its good to have a second opinion!