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Thread ID: 46045	2004-06-11 21:46:00	Subnet Mask ???	00falcon (3801)	Press F1

Post ID	Timestamp	Content	User
243564	2004-06-11 21:46:00	Ok... just trying to get it straight in my head... From what i gather... a Subnet Mask just defines which of the IP address octets are static and which are changable (for lack of better words). My network at home... 5 PC's on a 10Base T Network... HousePuter 10.10.0.1 GaragePuter 10.10.0.2 Win98 10.10.0.30 Fileserv 10.10.0.40 Svideo 10.10.0.50 All with the subnet Mask of 255.255.255.0 so with this Subnet Mask I can have 10.10.0.X where X is anything from 1 to 254...? What if i had a Subnet of 255.255.0.0... would that mean my network would do 10.10.X.X...? What would happen if on 2 of the Puters... I had a subnet of 255.255.255.1... if there is such a thing... Correct me if i wrong but is a subnet just so you can break your network up in to logical groups so that it speeds up routers and things...? Do you have to have a Subnet Mask...? Also in my event Viewer (XP) I have an "IPNATHLP" Error... saying ------------------------------------------- "The DHCP allocator has disabled itself on IP address 10.10.0.1, since the IP address is outside the 192.168.0.0/255.255.255.0 scope from which addresses are being allocated to DHCP clients. To enable the DHCP allocator on this IP address, please change the scope to include the IP address, or change the IP address to fall within the scope." ------------------------------------------- is this a problem or is it just as my IP's are not within the "Privately assigned" range of 192.168.X.X...? Is it a problem...? i have not noticed any adverse affects... P.S. very seriously looking at buying a book on Network+ as this will more than likely be my next course... Any recomended books... Ta Falcon	00falcon (3801)
243565	2004-06-11 22:46:00	All those PC's of yours should be on a Subnet range of 255.0.0.0 IIRC?!	Chilling_Silence (9)
243566	2004-06-11 23:42:00	Subnet mask is used to define the network side of the address and the computer side of the address . Looking at it in binary helps a lot . binary of 255 is 11111111 so S/N mask of 255 . 255 . 255 . 0 is 11111111 . 11111111 . 11111111 . 00000000 each range of IP addresses has a default subnet mask Class A 1 . x . x . x to 126 . x . x . x default is 255 . 0 . 0 . 0 (11111111 . 00000000 . 00000000 . 00000000 ) 127 . 0 . 0 . x is not usable . Class B 128 . . x . x . x to 191 . x . x . x is 255 . 255 . 0 . 0 (11111111 . 11111111 . 00000000 . 00000000 ) Class C 192 . x . x . x to 223 . x . x . x is 255 . 255 . 255 . 0 (11111111 . 11111111 . 11111111 . 00000000 ) At each 0 of the subnetmask you can have a computer in the same network (subnet) as the others so for a class A you can have the binary for x . 111111111111111111111111 which is 16,777,215 . You can't have all 0's or all 1's so you have to subtract 2 from the number of computers in the group . 16,777,215 - 2 is 16,777,213 computers in the same network by playing with the subnet mask you can eliminate the hugeness of the network but increase the complexity of the network . The theory is that you are supposed to buy the network address that you want . and if you have different departments in the company than you subnet net down and give each department a different subnet to play with . >>What would happen if on 2 of the Puters . . . I had a subnet of 255 . 255 . 255 . 1 . . . if there is such a thing . . . Subnetting goes from the left so you can not have a subnet mask of 1 . 10000000 =128 11000000 =192 11100000 =224 et c . NOT 111011xx that would be an invalid subnet mask because of the 0 in the fourth binary location followed by 1's . if you had ip address of the same range and then used different subnet masks the higher subnets will connect to the lower but ther lower would not connect to the higher because TCP will think they are out of the range so a S/N of 255 . 255 . 0 . 0 could connect to 255 . 255 . 255 . 0 but not the other way around >>Correct me if i wrong but is a subnet just so you can break your network up in to logical groups so that it speeds up routers and things . . . ? you are right . >>Do you have to have a Subnet Mask . . . ? yes EVENT VIEWER AFAIK you can only get DHCP on Internet Connection Sharing under WinXP Home your event viewer problem leads me to beleive that you have Internet connection sharing enabled on the XP Home PC . ICS uses a default IP of 192 . 168 . 0 . 1 as the ip of the computer and as a result of you not having the default IP address DHCP will not work . as it does not bother you don't worry about it . I hope i have not bored you and answered your questions without drivelling to much .	Wayne H (1736)
243567	2004-06-11 23:48:00	>>AFAIK you can only get DHCP on Internet Connection Sharing under WinXP Home Sorry I ment that WInXP home/pro can only have DHCP when ICS is turned on unless you have another program running the dhcp service that is not an MS product.	Wayne H (1736)
243568	2004-06-12 02:10:00	Primo Dude... All made sence... will be reading it a few more times before bed... :) yes i have got ICS enabled... out of curiosity... give my "Network Structure" what IP addresses would you use...? I started of useing addys in the 192.168.x.x range... but got tired of typing192.168.what.ever... so i changed to 10.10... i realise this is a class A IP range... is this bad...? P.S. i need to have static addresses Ta Falcon	00falcon (3801)
243569	2004-06-12 02:12:00	Again with the............. OK... 127.0.0.1... or LocalHost... is this how the computer refers to its self...?	00falcon (3801)
243570	2004-06-12 02:55:00	127.0.0.1 (or any address in 127. :O) is set to be localhost.localnet. It's used mostly as a test for the functioning of the TCP/IP software stack. A ping to 127.0.0.1 does not go through the hardware. By the way, a subnet mask is used to define the range of addresses in a local subnet (;-)) . For example, a 192.168.000.xxx by default allows 254 hosts., all of which have to look at all messages on the cable. In a large system, you might want to have different subnets for each work group or department. If they have their masks correctly set, the other groups are "invisible", and can only be reached if routing paths are set. Subnetting helps with the perceived shortage of 32bit IP addresses.	Graham L (2)
243571	2004-06-12 04:24:00	What's wrong with using the computername \\garage or \\gge on each PC create a LMhost file (got this info below from here. (www.pcworld.co.nz) Open the LMHOST file under the Windows directory. If there isn’t one, create one using Notepad. (Note that it has no file extension.) Enter the target’s IP address, a tab and then their machine name. (For example: 192.168.0.1 <tab> GEORGE.) If the machine name is two words, put them in quotes. Save and close the file. (thank you Geoff C) >>i realise this is a class A IP range... is this bad...? no it is not bad there are three universal ip address ranges that are classed as free to use inside your network they are 10.x.x.x (Class A networks that start with 10.) 172.16.x.x (Class B networks that start with 172.16.) 192.168.1.x (Class C networks that start with 192.168.1.) there is a good website I have just found so I will point you to that. Cisco (www.cisco.com) it says that Class a,b,c does not exist any more however people still use it very frequently. and i was wrong with my range earlier this morning as you will see from the cisco page. 128.x.x.x - 191.x.x.x not 192 like I had in my post this morning	Wayne H (1736)
243572	2004-06-12 04:29:00	I swear that I typed 128 to 192 but looking back at my posts I saw that I did not. fingers must finally be starting to autocorrect brain, gotta be more carefull of that for future.	Wayne H (1736)
243573	2004-06-12 09:54:00	There are a lot of good resources on the web to understand subnetting - a topic that is very logical but not easy to start with! For example: IP Addressing and Subnetting for New Users (www.cisco.com)	JohnD (509)
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