Wrong /24 Announcement at UU.net / BGP IOS Bug ?


one of our customers (germany.net, AS6751) is announcing us We announce this to our both upstreams
ECRC (AS1273) and Ebone (1755).

Since a few days a lot of german ISPs ask us, why
is routed via UU.net to the USA and then goes back to germany.

We checked our cisco-routers an finaly i found a Customer of UU.net
with a looking glass: (http://zeus.lyceum.com/cgi-bin/nph-bgp-routes)

QUERY: bgp
FROM: BR1.ATL1.lyceum.net.

BGP routing table entry for, version 9891827
Paths: (1 available, best #1, advertised over IBGP)
  701 1800 1755 1755 1755 5549 5549 6751 from (
      Origin IGP, valid, external, best

ok lets see bacK:

Sprint (1800) doesnt have this /24 but the /16 as it should be:

icm-bb4-pen#show ip bgp
% Network not in table

the same applies to EBONE (AS1755):

frankfurt-ebs1>show ip bgp
% Network not in table

an we (AS5549) also dont see any /24 out of

So the question is: why does UU.net announce and from
where do they get it. The worse thing is, that all uu.net customers get
this )(&%&$()& /24 from the hub in Frankfurt. The Space - is visiable at uu.net via

So what happens here, could this be an ios bug ?

We didnt touch our configuration towards ebone and they dont play
with their configuration every day :slight_smile:

Any ideas ? hints ?


PS: for the german isps, we fixed it by announcing only at de-cix the additionally to and it works, but
    i am still looking for an answer to my questions :slight_smile: ?

Hi Vinny!

As i am thinking about this, i came to the idea that mostly uu.net applies filters
to their downstreams
e.g. there are not filtering by as - they filter by access-list
what i presume is that they use a

access-list xyz permit

instead of (the correct one):

access-list xyz permit

note the difference ?

It's probably time for them to call the uunet support to fix this.

Winfried Haug wrote: