router subnet mask address & which to use for xbox 360?

[AledJ]

I have a belkin router and the subnet mask under internet settings is 255.255.252.0 but under lan settings its 255 instead of 252. Is that right?

[malfunction]

I have a belkin router and the subnet mask under internet settings is 255.255.252.0 but under lan settings its 255 instead of 252. Is that right?

Yes - it's just a filter (a bit mask) which tells the router which network segment it sits within - i.e. which IP addresses are part of the same network segment. Data for addresses outside of the local segment are sent down specific routes (probably just a single default gateway for an ADSL / cable modem) whereas data for the local segment is sent 'directly' to them (simplification).

It's kind of like when you drive into a town and you get sign posts that say 'this way to X' and 'that way to all other routes'.

If you're familiar with binary then:

255 = 11111111
  0 = 00000000
252 = 11111100

So in this context 255 means that *all bits* must match - i.e the number must be the same as the same segment of the local (interface) IP address. 0 means none of the bits have to match and 252 means that the first 6 bits have to match but the last 2 don't. You need to know both the IP address for the interface and the netmask to work it out. Examples ought to make it easier:

(here's the part where I find out if I'm awake or not - corrections ahoy)

Scenario #1

IP address 192.168.100.10, subnet mask 255.255.255.0

Means that all addresses in the 192.168.100.1 --> 192.168.100.255 range are local IP address - part of the same network segment (actually1 --> 254 IIRC because 255 is reserved for broadcast) are on the local network and can be contacted directly. I.e. in this case it's effectively using a filter of 192.168.100.* (the first three parts of the IP address - the 192, 168 and 100 parts - must match, the last part can be any value between 0 and 255)

Scenario #2

IP address 192.168.100.10, subnet mask 255.255.252.0

Means that the first two parts of the IP address must match - the 192 and 168 parts - but that the third part only needs to be a partial match (and as before the last part can be anything between 0 and 255). To make it clear we should turn the 100 into binary as well:

100 = 1100100
252 = 1111100

So what does this mean? It means that the third part must always start with "11001" but that the last 2 digits can be either 0 or 1. I.e. the mask / filter is "11001.."

In this case it means that the third part can be:

100 = 1100100
101 = 1100101
102 = 1100110
103 = 1100111

Mix that with the 4th part and what the 255.255.252.0 netmask says is that any address from 192.168.100.1 to 192.168.103.255 is part of the local network segment (i.e. 192.168.100.*, 192.168.101.*, 192.168.102.* and 192.168.103.* are all local addresses).

[AledJ]

Yes - it's just a filter (a bit mask) which tells the router which network segment it sits within - i.e. which IP addresses are part of the same network segment. Data for addresses outside of the local segment are sent down specific routes (probably just a single default gateway for an ADSL / cable modem) whereas data for the local segment is sent 'directly' to them (simplification).

It's kind of like when you drive into a town and you get sign posts that say 'this way to X' and 'that way to all other routes'.

If you're familiar with binary then:

255 = 11111111
  0 = 00000000
252 = 11111100

So in this context 255 means that *all bits* must match - i.e the number must be the same as the same segment of the local (interface) IP address. 0 means none of the bits have to match and 252 means that the first 6 bits have to match but the last 2 don't. You need to know both the IP address for the interface and the netmask to work it out. Examples ought to make it easier:

(here's the part where I find out if I'm awake or not - corrections ahoy)

Scenario #1

IP address 192.168.100.10, subnet mask 255.255.255.0

Means that all addresses in the 192.168.100.1 --> 192.168.100.255 range are local IP address - part of the same network segment (actually1 --> 254 IIRC because 255 is reserved for broadcast) are on the local network and can be contacted directly. I.e. in this case it's effectively using a filter of 192.168.100.* (the first three parts of the IP address - the 192, 168 and 100 parts - must match, the last part can be any value between 0 and 255)

Scenario #2

IP address 192.168.100.10, subnet mask 255.255.252.0

Means that the first two parts of the IP address must match - the 192 and 168 parts - but that the third part only needs to be a partial match (and as before the last part can be anything between 0 and 255). To make it clear we should turn the 100 into binary as well:

100 = 1100100
252 = 1111100

So what does this mean? It means that the third part must always start with "11001" but that the last 2 digits can be either 0 or 1. I.e. the mask / filter is "11001.."

In this case it means that the third part can be:

100 = 1100100
101 = 1100101
102 = 1100110
103 = 1100111

Mix that with the 4th part and what the 255.255.252.0 netmask says is that any address from 192.168.100.1 to 192.168.103.255 is part of the local network segment (i.e. 192.168.100.*, 192.168.101.*, 192.168.102.* and 192.168.103.* are all local addresses).

Thanks for the reply!! Some was over my head but I got most of it, and some things I never knew

[AledJ]

So if when I entered an ip address for the xbox and its sub net etc, I entered 255.255.255.0 but should have put 255.255.252.0 ?? I could log into xbox live with the 255.255.255.0 sub net in the settings, but would have a strict NAT even with UPnP being enabled.

[malfunction]

No - the xbox would only have a LAN IP address only and would use the 255.255.255.0 subnet (you *could* use something different but there's no need to unless you have more then 254 devices at home).

In fact there shouldn't be any need to enter an IP address or subnet mask on the xbox - just let it pick up a dynamic address from the router's DHCP server.

NAT in terms of home use just means that all traffic going out of the ADSL / cable router looks like traffic from the router itself.

[AledJ]

No - the xbox would only have a LAN IP address only and would use the 255.255.255.0 subnet (you *could* use something different but there's no need to unless you have more then 254 devices at home).

In fact there shouldn't be any need to enter an IP address or subnet mask on the xbox - just let it pick up a dynamic address from the router's DHCP server.

NAT in terms of home use just means that all traffic going out of the ADSL / cable router looks like traffic from the router itself.

Thank you! Only reason I asked was because I can't join friends xbox party/they can't join mine, although it did work once after new update. Wish microsoft would hurry up with a fix

[AledJ]

When I was trying to figure if my router was cause of not connecting to xbox party I did the following:

1. set an ip address for the xbox
2. enter gateway + subnet
3. enter dns for VM
4.opened required ports

Now before i did that my the last numbers in the xbox ip would be no more than 12, it would then go to 2, skip 3 (home pc), carry on and skip 5 (my laptop). But now instead of skipping if my laptop is not on it will take 5, when it started form the low numbers. It is now at 19 which I have never seen before, I know the pool address is 2>100. But any reason it has changed from rotating from 2>12?

[malfunction]

If you use DHCP then as your PC, laptop and xbox start up they each request an address from the network and the router sends them whatever it thinks the next free address is inside the configured DHCP range.

Sometimes the router appears to reuse the last address sent to that device, sometimes it doesn't - probably based on whether or not the client has released the address back to the router and / or if the lease on the address has timed out since you last used that client (PC, xbox, etc). Doesn't really matter in a home environment though as long as you are getting an address from the router and have net access everything should just work in this day and age (no need to use fixed addresses or open ports unless you explicitly know otherwise). Don't forget if you have a wifi enabled phone (or ipod or any other games console) they will also be using an address.

[AledJ]

Ok here is what I have tried so far in order to determine if my router is at fault or the last XBL update.

1. I set an ip address for the xbox, and changed everything I needed to- including opening ports (changed it back to how it was before- this made no difference)
2.I have checked an upnp is enabled
3. I have done the xbox network test and it says everything is running- no message about ti being strict ect- so can I assume the NAT is open?? After the test if I press Y i get this:

W 0000-000B
X 0000-F001
Y 20A8-4840
Z 0000-0000
ID- FFFF-FFFF

I have no idea what those codes mean!

4. Today I plugged the cable that goes to the power line adapter and put it directly inot the modem, but upon doing the network test it did not work- not sure why. (But i did not turn the modem power off when I did this would it make any difference?)

I am all out of ideas on this and would really appreciate some help I have looked to see if other people have had the same issues and there are one or two but not loads. Which makes me think I have an issue my end- but I have tried everything I can

Oh and I have tried clearing the cache.....but the bar that comes up does not move, and then the box disappears- I have restarted the xbox after doing this. And one more point- While playing black ops a friend of my friend invited us to a xbl party and it could join (black ops lost our connection after 40min), and I have briefly joined a fiends party (lasted 3 min).

[AledJ]

Any help guys???

Could those who have Balck Ops and can XBL party do the network test, and let me know when you press Y at the end what comes up?

[AledJ]

Just found out some interesting and confusing info. My netgear homplugs decided to die last night, and I did get them working but they had had it. When I went on the 360 into black ops to see if playing mp was ok after the homeplugs went down, I discovered that on the first mp menu there were options. So I selected it and and pressed < on the controller which then brought up a connection menu. It told me my NAT was open (great!)

But the homeplugs continued to cause issues so to rule out my port switch I connected my 360 directly yo the homeplugs, and when I went to the connection menu in black ops it said the NAT was strict. Now i'. confused as to how when connected to a network switch > to homeplug > router > modem, the NAT is open. But when I take the network switch out of the line the NAT is strict.

edit: the new netgear homeplugs I got say NAT is open when the network switch is connected, and when the 360 is connected directly to the homeplug.

[AledJ]

I know i have a lot of question, but could anyone help out?

[AledJ]

Today I had a look at the connection settings in msn and it said this- non-upnp symmetric nat

Now xbox live connection test is all ok (apart from that code bit above), black ops says NAT is open, and on my router homepage UPnP is enabled.

Thanks

[AledJ]

Check NAT was open in blakc ops today and was surprised to see it saying strict. Now upnp is enabled nothing has changed, so why the strict NAT? It did this about a week ago after I got some new netgear homeplugs.

Can anyone give me some help?

[watercooled]

Have you tried rebooting your router?

[AledJ]

Yes forgot to post back. But just confused as to why the NAT changed. Any ideas on - non-upnp symmetric nat- message in msn?