Visible Email Addresses and IP address Ban List

[SAT (aka GANDHI)]

Hey, I've been slowly adding ip ranges to my e-mail server as well to refuse smtp connections from the Asia Pacific Network, do you have a list of ip ranges handy?

APNIC is quite extensive.  This should cover most of it:

58.0.0.0/8
59.0.0.0/8
60.0.0.0/8
61.0.0.0/8
116.0.0.0/8
117.0.0.0/8
118.0.0.0/8
119.0.0.0/8
120.0.0.0/8
121.0.0.0/8
122.0.0.0/8
123.0.0.0/8
124.0.0.0/8
125.0.0.0/8
126.0.0.0/8
169.208.0.0/12
202.0.0.0/8
203.0.0.0/8
210.0.0.0/8
211.0.0.0/8
218.0.0.0/8
219.0.0.0/8
220.0.0.0/8
221.0.0.0/8
222.0.0.0/8

What does the /8 and the /12 mean after the IP address?
Would that be the first 8 and first 12 in that particular address (i.e. 210.0.0.1, 210.0.0.2, 210.0.0.3 ... 210.0.0.8)?

Thanks!
Joe

[SAT (aka GANDHI)]

That's the subnet mask, separates the network bits from the host bits

/8 = 255.0.0.0
/12 = 255.255.0.0


It's shorter to denote the mask this way than use the dotted decimal.

[SAT (aka GANDHI)]

What does the /8 and the /12 mean after the IP address?
Would that be the first 8 and first 12 in that particular address (i.e. 210.0.0.1, 210.0.0.2, 210.0.0.3 ... 210.0.0.8)?

Thanks!
Joe

"/n", or /8 and /12 in this example, is called the IP prefix or network prefix in CIDR notation.  For example, when I say 59.0.0.0/8, I'm telling you I'm referring to all of the possible addresses in the range of 59.x.x.x.  /8 also signifies a Class A address range and also the number of significant bits used to identify a network (i.e., the netmask).  If I were to say an IP address of 59.10.34.113 had a netmask of 255.0.0.0, this is also equivalent to /8.  The most common are Class A (/8 or 255.0.0.0), Class B (/16 or 255.255.0.0) and Class C (/24 or 255.255.255.0).  To specify an exact address, use /32 as the notation.  In my example, if I referred to 59.10.34.113/32, I am talking about that exact address - /32 is equivalent to a netmask of 255.255.255.255.

Not sure how to explain this without referring someone to IPv4 TCP/IP FAQs.  IP addresses were assigned as blocks/ranges way back when.  And in a haphazard fashion too.  There was and still is a lot of wasted IPv4 address space out there, especially with a few Class A ranges.  I work for NOAA, which 'owns' all of the 140.90.x.x Class B address space and a surprising amount of that space is still unused.  It's actually kinda pathetic because we are running out of IPv4 space.  Slowly, but surely.  That's why IPv6 is a hot item, but that's a whole other discussion that makes my brain hurt.

[SAT (aka GANDHI)]

That's the subnet mask, separates the network bits from the host bits

/8 = 255.0.0.0
/12 = 255.255.0.0


It's shorter to denote the mask this way than use the dotted decimal.

Actually the correct netmask for a 12 bit IP range number is 255.240.0.0 the second octet is only a 4 bit number so 256 - 16 (2^4) - 240, thus the netmask.
a 255.255.0.0 netmask is a /16 address.  In the range given in the example

169.208.0.0/12 the valid addresses in that range is 169.208.0.1 - 169.223.255.254  (208+16-1 (since you start at zero) gives you the range of addresses valid for that subnet)

The addresses at the ends are referred to the network and the broadcast in this case 168.208.0.0/12 is the network and the 169.223.255.255 is broadcast.

[SAT (aka GANDHI)]

.... NERDS! 

[SAT (aka GANDHI)]

.... NERDS! 

 

I'd like to think as just knowing the stuff I work with everyday. 

[SAT (aka GANDHI)]

.... NERDS! 

 

I'd like to think as just knowing the stuff I work with everyday. 

Right.  But we're still nerds.

[SAT (aka GANDHI)]

Nerd = Network
           Emergency
           Response
           Dude

The network is the computer....

[SAT (aka GANDHI)]

Actually the correct netmask for a 12 bit IP range number is 255.240.0.0

DOH!

You're right, gives you an idea of how much mush my brain is after a week in the pressure cooker I call work.

[SAT (aka GANDHI)]

Thanks and Karma + to JohnnyG, brichter, and Rick for your explanation of the /n.  Once again I learned something new today (as Rick's tag line states). But I can see that it is only the tip of the iceberg on IP address's.
Looks like I have some reading to do! 

[SAT (aka GANDHI)]

Thanks and Karma + to JohnnyG, brichter, and Rick for your explanation of the /n.  Once again I learned something new today (as Rick's tag line states). But I can see that it is only the tip of the iceberg on IP address's.
Looks like I have some reading to do! 

Funny how some turd keeps giving me Bad Karma.  So your Karma+ actually brought it up to one number less than it was last night.

How amusing.

If I change my pic to some 24 y/o hottie, will that get me more Karma+?

[SAT (aka GANDHI)]

good karma for all.

W

[SAT (aka GANDHI)]

If I change my pic to some 24 y/o hottie, will that get me more Karma+?

A 24 y/o hottie is always appreciated