Packets from net 10 (no, not the lyrics)
Alec H. Peterson
ahp at hilander.com
Tue Sep 23 20:49:25 UTC 1997
On Tue, Sep 23, 1997 at 04:43:16PM -0400, Todd R. Stroup wrote:
>
> I disagree.. how about this:
>
> access-list 50 deny 0.0.0.0 0.0.0.31
>
> or for those brave folk:
>
> access-list 50 deny 0.0.0.0 0.0.0.255
>
> The extended access-list is used in the classic "FROM ip" and "TO
> ip" application. My point was to use the standard access-list
> applied to a BGP session. The only thing I can think of that you
> would need a FROM/TO senerio in would be peering with Route Servers,
> although in this case I use route-maps filtering on path and by
> address. I don't even think an extended access-list will apply to a
> bgp session, but I could be wrong.
Uhm, your example wouldn't work too well if one wanted to selectively
filter longer prefixes (like all longer than /19 in 206->223). That
is what many people are doing, and IMO what more should do.
>
> Your BGP peer config is going to look something like this with a standard
> access-list :
>
> router bgp 7171
> neighbor 198.32.69.69 remote-as 6969 ; sorry about your luck N2K Inc.
> neighbor 198.32.69.69 version 4
> neighbor 198.32.69.69 distribute-list 50 in
> neighbor 198.32.69.69 route-map as-customers out
>
> access-list 50 deny 0.0.0.0 0.0.0.0
> access-list 50 deny 0.0.0.0 0.0.0.31
> access-list 50 deny 127.0.0.0 0.255.255.255
> access-list 50 deny 10.0.0.0 0.255.255.255
> etc...
Yes yes, but this really limits what you can do.
How would you do:
access-list 101 permit ip 206.0.0.0 0.255.255.255 0.0.0.0 255.255.224.0
with a standard access list?
Alec
--
+------------------------------------+--------------------------------------+
|Alec Peterson - ahp at hilander.com | Erols Internet Services, INC. |
|Network Engineer | Springfield, VA. |
+------------------------------------+--------------------------------------+
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