24.0.0.0 and Sprint/AGIS filters

Alec H. Peterson ahp at hilander.com
Wed Feb 19 13:25:47 UTC 1997


On Feb 19, 1997, Hank Nussbacher wrote:
> How is @Home managing to pass these nets pass Sprint and AGIS with their
> prefix filtering rules?
> 
> *>i24.0.0.0/18      192.121.156.41              100      0 1800 1239 6172
> i
> *>i24.0.0.0/14      192.121.156.41              100      0 1800 1239 6172
> i
> *>i24.1.0.0/17      192.121.156.41              100      0 1800 1239 6172
> i
> *>i24.48.0.0/18     192.121.156.41              100      0 1800 1239 1673
> 1677 ?
> *>i24.64.0.0/19     192.121.156.41              100      0 1800 1239 1794
> 3602 3602 3602 6327 6327 i
> *>i24.64.32.0/19    192.121.156.41              100      0 1800 1239 1794
> 3602 3602 3602 6327 6327 6327 i
> *>i24.88.0.0/18     192.121.156.41              100      0 1800 1239 3561
> i
> *>i24.96.0.0/18     192.121.156.41              100      0 1800 1239 1791
> 6541 i
> *>i24.108.0.0/18    192.121.156.41              100      0 1800 1239 3561
> 577 852 i
> *>i24.112.0.0/18    192.121.156.41              100      0 1800 1239 1793
> 6463 i
> *>i24.112.32.0/19   192.121.156.41              100      0 1800 1239 3561
> 2493 8
> *>i24.113.0.0/18    192.121.156.41              100      0 1800 1239 6177
> i
> *>i24.113.32.0/19   192.121.156.41              100      0 1800 1239 3561
> 2493 812 i
> *>i24.124.0.0/18    192.121.156.41              100      0 1800 1239 3561
> i
> *>i24.128.0.0/18    192.121.156.41              100      0 1800 1 560 7015
> i
> *>i24.129.0.0/18    192.121.156.41              100      0 1800 1 7017 i
> *>i24.131.0.0/18    192.121.156.41              100      0 1800 1 5638
> 7016 i
> *>i24.131.128.0/18  192.121.156.41              100      0 1800 1 7756 i
> *>i24.192.0.0/18    192.121.156.41              100      0 1800 1239 3561
> 1221 i

Sprint probably decided to apply the standard /19 filter to the IP
space in 24/8 since the InterNIC is allocating subnets in it.  All of
the networks you cite have masks that are /19 or shorter.

So the answer is, 24/8 is a special case.

Alec

-- 
+------------------------------------+--------------------------------------+
|Alec Peterson - ahp at hilander.com    | Erols Internet Services, INC.        |
|Network Engineer                    | Springfield, VA.                     |
+------------------------------------+--------------------------------------+





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