From: Ian Stong (istong@stong.org)
Date: Thu Jun 24 2004 - 08:42:46 GMT-3
Hi,
Koen is correct. There are other networks you can/should consider
blocking that are part of the list known as Bogons/Martians/RFC1918 as
follows:
0.0.0.0/7
2.0.0.0/8
5.0.0.0/8
7.0.0.0/8
10.0.0.0/8
23.0.0.0/8
27.0.0.0/8
31.0.0.0/8
36.0.0.0/7
39.0.0.0/8
41.0.0.0/8
42.0.0.0/8
49.0.0.0/8
50.0.0.0/8
71.0.0.0/8
72.0.0.0/5
89.0.0.0/8
90.0.0.0/7
92.0.0.0/6
96.0.0.0/3
169.254.0.0/16
172.16.0.0/12
173.0.0.0/8
174.0.0.0/7
176.0.0.0/5
184.0.0.0/6
189.0.0.0/8
190.0.0.0/8
192.0.2.0/24
192.168.0.0/16
197.0.0.0/8
198.18.0.0/15
223.0.0.0/8
224.0.0.0/3
Note that the list is somewhat dynamic so you should update it
periodically.
Thanks,
Ian
http://www.ccie4u.com
Rack Rentals and CCIE Lab Scenarios starting at $20
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Koen Peetermans
Sent: Thursday, June 24, 2004 5:23 AM
To: 'Geert Nijs'; ccielab@groupstudy.com
Subject: RE: Class A network
Geert,
It's safe to block this. It's not used on the internet and should not be
coming into your router as a source address.
If you look at the autosecure 12.3 feature, it is blocked as well :
http://www.cisco.com/en/US/products/sw/iosswrel/ps5187/products_feature_
guid
e09186a008017d101.html
Kind regards,
Koen.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Geert Nijs
Sent: donderdag 24 juni 2004 10:53
To: ccielab@groupstudy.com
Subject: Class A network
Hi group,
I just came across an ACL on an internet router containing the line:
access-list 110 deny ip 0.0.0.0 0.255.255.255
And i was wondering, the first class A network: 0.x.x.x
Is this a valid network ? Is this network distributed to a company on
the
internet ??
If so, then i can't filter it off.
If not official, i can filter it completely off to prevent hackers
spoofing
these addresses.....
Regards,
Geert
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