[j-nsp] OSPF default problem

[Felix Schueren]

Cord MacLeod wrote:
> NAT works fine on the 3560.  The ex4200 can ping from 10.0.0.2 (its
> local l3 interface) to 10.0.0.1 (the 3560's local interface).  The
> ex4200 can already hit the internet.  It's the other devices that seem
> to be having an issue.  They cannot hit 10.0.0.1.  The ex4200 is not
> using vlans as of yet, only routed interfaces with ospf.
> 
> The config for the ex4200 I've already emailed to the list along with
> the routing tables.  As far as the 3560:
> 
> interface Vlan666
>  description TEMP VLAN FOR JUNIPER GEAR
>  ip address 10.0.0.1 255.255.224.0
> !
> interface GigabitEthernet0/20
>  description TEMP FOR JUNIPER GEAR
>  switchport access vlan 666
>  duplex full
>  speed 1000
> 
> As a note the /19 for the netmask is for BGP to advertise this block as
> a /19.
> 
> 
as Joe and I have pointed out, the problem is most likely that your 3560
does not have any routes back towards the "other devices" and will try
to reach them via plain Layer2 on the Link between the C3560 and the
EX4200 - also note that for BGP injection a recommended technique is
creating the full network (/19 in this case) as a static discard / null0
route, then assigning more specifics out of the /19 (and distributing
them into your IGP). This has the added benefit of blackholing all the
unassigned space out of the /19.

I highly recommend fixing your addressing (which I'd consider "broken"),
then checking your routes on the 3560.

Kind regards,

Felix


-- 
Felix Schüren
Head of NOC

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