| THIS IS A READ-ONLY ARCHIVE FROM THE SORABJI.COM MESSAGE BOARDS (1995-2016). |
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123.456.789.0/22 (So, I'm looking for something like 123.456.84-100.* or whatever it is) Thanks! |
do you need a subnet mask for that range? |
No, no subnet mask. Our system deals with ranges only (I don't know if there's a technical term for this....please excuse my ignorance), so I need every IP translated out of subnet notation and into, you know, just straightforward xxx.xxx.xxx-xxy.* notation. The note I received reads, "Our network is 123.456.789.0/22. Your networking people should understand what that means." Only, I'm the networking person, and I don't understand what that means. Sheesh, my job gets better and better... |
123.456.80-95.* |
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It's 123.456.84-87.* |
is 22 the name of a directory? it all depends on what you're trying to do with the info. i'm inclined to say they have 22 dynamic ips on a class c subnet. |
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Dave, I wish I could tell you...I'm next to clueless about this stuff. I work for an online research database -- we have to input your IPs in our system in order to grant you access to our websites. Our IP Address Table only accepts IPs in, like, standard notation. (E.g., 123.45.67-89.* or 123.45.67.* or 123.45.67.89). We can't deal with subnets, network masks, or anything like that. |
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Never reveal the following information in a public forum: 1) The method your company uses to verify user identity. 2) The identification information a client is using. 3) The subscription status of a current client. I leave it as an exercise for the student to discover how an attacker can gain access to the system using this information... |
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Or giraffes. Or ibexes. Or elk. |
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i even took a half day long course in subnetting, but i never saw anything in xxx.xxx.xxx.0/xx format. perfect example of why knowing a little bit is much more dangerous than knowing nothing. i sometimes think i lack the capacity to learn anything in depth. i have a real talent for learning about anything up to a point. it's like i was born with a beginners course knowledge of everything but i can never get beyond that point. fuck, i abhor being wrong. i always seem to be wrong. |
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Take 8 binary digits and write them out from highest on left to lowest on right: 128 64 32 16 8 4 2 1 Then starting at 128 from left to right, add the number next to it to get the next subnet mask: 128 192 224 240 248 252 254 255 If somebody gives you 172.16.1.0/22 the /22 means the number of bits in the subnet which would be 255.255.252.0 or 11111111.11111111.11111100.00000000 in binary (there should be 22 "1's"). Assuming you're using "0" subnets (meaning a subnet may start on 0, such as 172.16.0.1) the first valid subnet would start on 172.16.0.1 and would go up to 172.16.3.254 (as valid hosts). To find the next subnet, you take the number you used for the netmask (.252) in your table you wrote out above -- it's 3 places from right. Then use your binary digits table you wrote out, and take the number 3 places from the right which is 4. This is the number you increment with to get to the next subnet. Thus, 172.16.4.0 is the next valid subnet. For the number of networks that are valid in this subnet, for .252 in your table, you count from left to right 6 bits. 2^6 = 64 valid subnets (going from 172.16.0.0 to 172.16.252.0) To find the number of hosts for each subnet, you count the number of 0's in the host portion (255.255.252.0 in binary is: 11111111.11111111.11111100.00000000) Everything that's a zero is host portion, which gives you 10 bits of zeroes. 2^10 - 2 = 1022. You must subtract 2 because one is the actual network or wire, and one is for the broadcast address in each subnet. Have fun with this, and then we'll move onto supernetting. Hope this helps. |
Screw it, I'll post it here. Let me know if I should make any corrections: ************** An IP consists of four groups of numbers, called octets, separated by dots. Ex: 111.222.33.44 Each octet has a maximum limit of 255, so if a customer sends you something like 204.279.30.9, you will know there is a typo in the second octet. An asterisk, or wildcard, is a shorthand way of writing 1-255. 102.45.78.* is the same as 102.45.78.1-255 A zero acts as a network holder, so it acts as a wildcard or a 1-255 range. Ex: 102.45.78.0, for example, is equivalent to 102.45.78.* and 102.45.78.1-255 in our system. If a customer gives you an IP that contains a range beginning with 0, like 102.45.0-16.*, you need to rewrite this as 102.45.1-16.* when you submit it to Dayton. Otherwise, when our system sees the zero, it will read it as a network holder and translate the IP to 102.45.1-255.* or 102.45.*.*. A customer might submit a block of IPs like this: 102.45.70.* 102.45.71.* 102.45.72.* 102.45.73.* You should rewrite this as 102.45.70-73.* when you submit the request to Dayton. Whenever you have a range in a certain octet (like 70-73 in the third octet above), all the following octets must have wildcards (*) in them. So 102.45.70-73.* has an asterisk in the fourth octet, and if you were sent something like 102.45.*.* 102.46.*.* 102.47.*.* …you would rewrite this as 102.45-47.*.* with the asterisks in the third and fourth octets. Our system does not accept subnet notation (e.g., 102.45.78.0/24), so all IPs that come to you in this format must be translated into simple range notation. Use an IP calculator (like http://jodies.de/ipcalc ) to do this for you, or ask the customer to reformat the IP into range notation. You might also get something like this: 193.1.1.0 255.255.255.224 Whenever you see anything like 255.255.255.224, this is a subnet mask. Another common one is 255.255.255.0. Our system does not accept subnet masks, either, so you need to translate these with the IP calculator or ask the customer to reformat the IPs into range notation. In our example’s case, the calculator gives you a result of 193.1.1.1-254 or 193.1.1.* ******************** |
. Whenever I have to teach someone about IP addresses, I can't resist trying to give them a lesson in binary so they understand how netmasks and subnets work and can figure them out by hand... which never goes well. _I_ think it's really nifty. Why doesn't anybody else? |
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