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I thought I was suppose to use a zero for the last three ranges, but it appears that doing so does not all any IP such as 10.123.123.123 or 10.1.1.1 to get through. How should I be doing this? Thanks
Code:
14 ACCEPT tcp -- 10.0.0.0/24 0.0.0.0/0 tcp dpt:445 state NEW
Last edited by NotionCommotion; 04-08-2017 at 11:57 PM.
Your netmask should be just the first 8 bits, not the first 24:
Ah, I think I finally starting to get this IP thing. Let me explain my current understanding, and please correct me where I am wrong.
All IPv4 require 32 bits, and a given network can have?
(1) class A network with 2^24 IPs (16,777,216) where the remaining 8 bits are used to specify it is a class A network?
(16) class B networks with 2^20 IPs (1,048,576) where 8 of the remaining 12 bits are used to specify it is a class B network and the remaining 4 bits are used to specify which of the 16 (172.16 to 172.31) it is?
(256) class C networks with 2^16 IPs (65,536) where 8 of the remaining 16 bits are used to specify it is a class C network and the remaining 8 bits are used to specify which of the 256 (198.168 to ???) it is?
So, then these remaining 8, 12, or 16 bits are used to mask the IP so they don't conflict with others?
To be fair, Class A, Class B and Class C subnetworking isn't really used anymore, rather everything went to CIDR notation where Class A is equiv of a /8, Class B a /16 and Class C a /24 where the notation indicates the number of bits within the network address. CIDR is generally all round better, tho I am guessing Colleges and Universities probably still the old class style of subnetworking... cas those places usually get stuck in the past.
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