Last month, IANA allocated the 1.0.0.0/8 and 27.0.0.0/8 networks to APNIC (the Internet registry for the Asia-Pacific region), pushing the total IPv4 address space utilization above the ominous 90% mark. Passing this benchmark should not come as a surprise to anyone, given the painfully slow adoption of IPv6. But what's interesting about the first range in particular is the amount of junk traffic already present.

As part of an effort to de-bogonise this newly allocated address space, RIPE, in cooperation with APNIC, made some test advertisements to ...

IOS prefix lists work like access lists for route advertisements (prefixes). While extended (and to a limited extent, standard) access lists can be employed to match prefix announcements, prefix lists are generally more graceful. Prefix lists work very similarly to access lists; a prefix list contains one or more ordered entries which are processed sequentially. As with access lists, the evaluation of a prefix against a prefix list ends as soon as a match is found.

Assume you wanted to prevent a route for 10.0.0.0/24 from being redistributed from OSPF to BGP. One way to accomplish ...

As Greg Ferro of Etherealmind has pointed out, IOS 15.0 will be introducing some significant complexity into the way we install and manage IOS images on Cisco routers. This brings some potentially devastating changes to the way we've been maintaining IOS devices for the last decade or so.

Up to and including IOS 12.4, the software image to be installed on a device depended on the feature set purchased from Cisco (as well as the device's physical hardware capabilities). With the latest major IOS revision, Cisco introduced a more modern (read: painful) approach to feature activation ...