Author Topic: What do I need two NICs for?  (Read 2062 times)

tschak909

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Re: What do I need two NICs for?
« Reply #15 on: September 23, 2009, 12:28:01 pm »
If you want to understand why things are structured the way they are, check out the code and dig in.

-Thom

wierdbeard65

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Re: What do I need two NICs for?
« Reply #16 on: September 23, 2009, 12:34:06 pm »
Well, if you are not planning on leaving it on all the time, then it can't be the DHCP for your network etc.

I'm kind of where you are.... What I've done is to leave my existing network alone. My test Core (I'm going for dedicated) is just a node on my internal network and is turned off when I'm not playing with it. I have the 2nd NIC and switch and my 1 MD is connected to that. Again, when I'm not playing, both are switched off.

Now, once I have got it all working, put in a production Core and, mopst importantly, got Family (well, wife!) buy-in, I will leave the core on and migrate my existing machines to the "internal" network.

The problem you have is that the whole way MCE "knows" about new devices is from their DHCP request. If it isn't the DHCP server, then it can't detect the devices and you've cripled the system. Add on to that that your MDs are diskless, so rely on DHCP to do a PXE boot from your core and you have a stack of broken bits.

As I said at the start, if you turn off your core, then it can't be your DHCP derver since the rest of your network will be without "leadership". (In your suggestion about putting your router on the "internal" network, you didn't mention wanting to turn your core off ;) )

On the cabling front, do you already have Cat5 to your location for your Core? If not, 2 cables isn't much more than 1. If so, you can always get splitters that let you use a single Cat5 / RJ45 for two connections. Alternatively, you could get clever and put in a mini switch and use VLans. There are lots of possibilities.

Finally, noise. That's one of the reasons I'm going for a dedicated core. Put it somewhere where the noise doesn't matter :D (Garage, under stairs or wherever).

HTH
Paul
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totallymaxed

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Re: What do I need two NICs for?
« Reply #17 on: September 23, 2009, 01:06:38 pm »
As everyone here is saying, why make work for yourself? Life's too short as it is!
First reason: Because I am a bit stubborn and would like to understand the reasons for limitations that cause me trouble :)
Second reason: Wiring will be tough.
Third reason: I like the ideas behind LinuxMCE and will probably be using many features in the future. But currently, I just want to do the first small step and do not need an always-on-media-server. But what I do need is an always-on-router for the internet-access. Thus the idea was to be able to turn the core/md off when it is not needed. An always-on-machine consumes more electricity and there is the risk of it being too loud for the living-room. When we are watching TV, the noise does not disturb anybody. But what about reading a book? Thus the one-NIC-approach is quiet charming.

The simplest solution for the moment seems to be to install XP-MCE or some other MCE-Solution that does not go as far as LinuxMCE for the moment. But I don't want to give up that easily :)


In our customer installations we always fit two NIC's  - one WAN side that hooks up to the broadband router and gets its address from the router by DHCP, and the other NIC is LAN side and this would then have a Switch (or switches) attached to it to distribute the LAN around the property...the LAN side would get its DHCP offers from the Core. This installation assumes that at least the Core is on 24/7 otherwise DHCP and other services are lost.

....now in my home installation I have a single NIC (because my Core is creaky and old and has few slots!!) and my broadband router has its DHCP turned off on its LAN side. My Core attaches to one of the broadband routers ports and is the DHCP server on the LAN. It therefore must be switched on 24/7 as otherwise DHCP would fail...but also so would my families TV and DVD consumption ;-). The Core is always running becuase its always doing something...even in the middle of the night it is usually recording some weird TV show or movie...so we never turn it off (it uses about 42W).

Hope the above is helpful.

Andrew
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AndiHoffi

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Re: What do I need two NICs for?
« Reply #18 on: September 23, 2009, 01:11:37 pm »
The problem you have is that the whole way MCE "knows" about new devices is from their DHCP request. If it isn't the DHCP server, then it can't detect the devices and you've cripled the system.
Good point. I forgot about that. So it has to remain always on...

AndiHoffi

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Re: What do I need two NICs for?
« Reply #19 on: September 23, 2009, 01:15:05 pm »
....now in my home installation I have a single NIC (because my Core is creaky and old and has few slots!!) and my broadband router has its DHCP turned off on its LAN side. My Core attaches to one of the broadband routers ports and is the DHCP server on the LAN. It therefore must be switched on 24/7 as otherwise DHCP would fail...but also so would my families TV and DVD consumption ;-). The Core is always running becuase its always doing something...even in the middle of the night it is usually recording some weird TV show or movie...so we never turn it off (it uses about 42W).
Sounds like the setup I was thinking about (except the always-on, but I think, I have to live with that). After some other posters wrote that it was very hard to set up, can you please write some more information about the trouble you had to go through to get this to work?
Thank you

totallymaxed

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Re: What do I need two NICs for?
« Reply #20 on: September 23, 2009, 01:27:40 pm »
....now in my home installation I have a single NIC (because my Core is creaky and old and has few slots!!) and my broadband router has its DHCP turned off on its LAN side. My Core attaches to one of the broadband routers ports and is the DHCP server on the LAN. It therefore must be switched on 24/7 as otherwise DHCP would fail...but also so would my families TV and DVD consumption ;-). The Core is always running becuase its always doing something...even in the middle of the night it is usually recording some weird TV show or movie...so we never turn it off (it uses about 42W).
Sounds like the setup I was thinking about (except the always-on, but I think, I have to live with that). After some other posters wrote that it was very hard to set up, can you please write some more information about the trouble you had to go through to get this to work?
Thank you

As ever the Wiki is your 'friend' in this type of situation ;-)

Look at this page for the steps needed to go with a single NIC; http://wiki.linuxmce.com/index.php/DHCP_Plug_and_Play

My setup is the same as described except that the externally facing fixed address for my Core is 192.168.20.99 and my broadband router is on a fixed address of 192.168.20.1 (ie they are in the same subnet)

All the best

Andrew
Andy Herron,
Convergent Home Technologies Ltd
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AndiHoffi

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Re: What do I need two NICs for?
« Reply #21 on: September 23, 2009, 03:04:55 pm »
As ever the Wiki is your 'friend' in this type of situation ;-)

Look at this page for the steps needed to go with a single NIC; http://wiki.linuxmce.com/index.php/DHCP_Plug_and_Play
Thank you very much. I did not find this page during my initial search.

Regards
Andreas