Junos OS

Hi,

Quick look at topology:

3a05:d840:0060:ff46::0/64 prefix --> xe-1/2/4.10 MX240 Core --> MX240 Core xe-1/2/5 --> Upstream Peer

On the MX core I am advertsing the following to the eBGP upstream peer:

3a05:d840::/29

If I perform a route lookup for the "3a05:d840:60:ff46:701c:c6b7:44d5:d26b" IPv6 address, I am getting the following response:

user@test# run show route 3a05:d840:60:ff46:701c:c6b7:44d5:d26b

inet6.0: 50636 destinations, 50636 routes (50636 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3a05:d840::/29 *[Aggregate/130] 2w1d 18:58:15
Reject

Not sure why it is showing the route as rejected. Here are the advertsied IPv6 Networks:

Clive@THW-CORE-01# run show route advertising-protocol bgp 211a:978a:2:21::1de:1

inet6.0: 50634 destinations, 50634 routes (50634 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 3a05:d840::/29 Self I
* 3a05:d840:26::/48 Self I

Any ideas what could be causing this?

I have the bogon listing that is automated rejects from the Cymru guys, but I cannot see anything wrong there....

Thanks

Hi,

3a05:d840::/29 route is showing as aggregate route. By default, the next-hop type of aggregate route is "reject"

Please check if you have configured any aggregate route

Yep, Certainly have:

set routing-options rib inet6.0 aggregate route 3a05:d840::/29 policy aggregate-route-ipv6

set policy-options policy-statement aggregate-route-ipv6 from protocol direct
set policy-options policy-statement aggregate-route-ipv6 from route-filter 3a05:d840:26::/48 orlonger
set policy-options policy-statement aggregate-route-ipv6 from route-filter 3a05:d840::/29 orlonger

Aggregates have to advertised upstream. Would this affect routes back? It does not seem to affect a route back to the LNS DSL Customers as they are working with IPv6 in that prefix range (3a05:d840::/29).....

After a quick check, it does indeed cause an issue as a traceroute show "no route to host" as it will with a reject.

Thanks

Hi,

Which IP and from where you are tracing? If there is no specific route for traced IP in MX routing-table, it will match the aggregate route and will reject the packets and send the ICMP Destination network unreachable response to client. This is an expected behaviour. 

All is cool. 

I don't think the "reject" actual stops anything working unless you try and do something direct from the MX240 Core router itself.

An example would be as follows:

CPE has address 3a05:d840:ff45:0060::1 - this falls within the prefix and ALSO shows as reject on the core. However, if I perform a ping and traceroute to facbooks IPv6 address, it all works fine. So, I think the "reject" on the core is a red herring.

I will close this. Thanks for the advice regarding the aggregate route....