This guide was written for a tm9100 but is relevant for all stbs used in sharing.
Thanks to sonoftechno for the info.
Subnet mask:
Each bit that is on(1) in the subnet mask has to be on(1) in the IP of any device that wishes to join that subnet and each bit that is off(0) can be on(1) or off(0) in the joining device. This means that 255.255.255.0 says that the first three digits of any device that wishes to join the subnet has to match EXACTLY. The last digit can be any number between 1-254. In normal home operation 255.255.255.0 is 'normal'.
Default Gateway:
The default gateway is a device that has an IP on the local subnet and also has access to another subnet(network) e.g. the internet. The local IP has to follow the rules for all devices, based on the subnet mask, to be part of the local network. This entry is required to gain access to the internet (typically), but is not important if you only want to have connectivity between your PC and your TM9100, which should both be on the local subnet.
DNS:
DNS is a protocol used to resolve hostnames to IP addresses. To reach a computer you need to find its IP address and this is done by DNS. For example when you enter www.EXAMPLE.co.uk the name has to be translated to an IP (69.46.27.83) and this is done by DNS which is made up of very many DNS servers that have the lookup tables for all site names to IP addresses for all sites in the world. If you access a site by using the IP address then DNS is not used and not required.
DHCP:
DHCP is a mechanism used to allocate IP addresses to devices in a subnet. When a device is started it asks the DHCP server for an IP address. The DHCP server issues the IP address with a 'lease time' (time that device owns that IP). This means that devices n a network that use DHCP can be issued with a different IP each time they are started or the lease expires. This is not a good situation for the connection between the PC and the TM9100 as changing IP addresses make it difficult to connect DCC.TCC/STBManager. That is why it is recommended that the network be set up with STATIC IPs (not using DHCP). Before the previous gets attacked - this is not an absolute requirement, but it will make life for newbies much easier.
Static IP
A static IP is an IP that is assigned to a device and remains the same regardless of whether the device is restarted or not. This is the prefered way to set up your TM9100 as it ensures that it always has the same IP and therefore it is much easier to connect to it. If you leave the DHCP box ticked in SETUP/EXPERT/COMMUNICATIONS SETUP, then the IP could (and most likely will) keep changing. When you untick the DHCP box you will be allowed to enter a static IP in the "IP" box.
SO, to get your PC connected to your TM9100 you only need to set the subnet mask and IP adresses correctly and turn off DHCP(at least on the TM9100). If you also wish to access the internet, you have to set the default gateway correcly and if you wish to use domain names(site names) to access the internet you have to set up your DNS correctly.
NOTE
I did not discuss home networks that do not have a router to connect to the internet as I don't believe that to be a good solution and do not recommend it at all. Furthermore you have to have internet access to get full value out of your Linux STB, so connection with crossover cables are also not discussed.
The following would be a typical setup:
ROUTER: DHCP Server = no
IP = 192.168.1.254
subnet=255.255.255.0
PC:
DHCP = no
IP = 192.168.1.1
subnet=255.255.255.0
DNS= (as provided by your ISP)
default gateway=192.168.1.254
TM9100: DHCP=no
IP=192.168.1.100 (use a larger number in case there are DHCP devices on the subnet)
subnet=255.255.255.0
DNS= (same as for PC)
default gateway=192.168.1.254
