Junos OS

Hello Guys 

I have been trying to find the answer for this particular question

The question is as follows

Hello,

In JUNOS routing policies the "from route-filter" statement uses longest match.

So in Your example, 1.1/17 will match "1.1/17 upto /24 reject" clause, the 1.1/17 route will be rejected and "from" match condition will return FALSE. No metric or accept action will be applied.

HTH

Regards

Alex

Dear Alex

According to the official "UPTO"statement

upto The upto match type provides the router with a starting prefix and an ending prefix

length. The match type locates the route specified in the route filter and starts to match all routes

more specific than the specified route.

Actually the portion highlited in red is a bit confusing to me.

So if the route filter matches 1.1/17 prefix and tries to find something more specific it wont find anything and hence there will be no match.

What do you think regarding this statement highlighted in red.

Regards

Malik

Hello,

JUNOS routing policy processes one route at a time. If You have only 1.1/17 route then it will be rejected by Your policy.

This policy will NOT actively look for any other routes in any routing tables, You need the "condition" match statement for this to happen.

HTH

Regards

Alex

Thank You Alex

Can you please provide one such example.

Regards

Malik

Sure

policy-options {
    policy-statement check1 {
        term 1 {
            from {
                protocol aggregate;
                route-filter 1.129.0.0/16 exact;
                condition route1;
            }
            then accept;
        }
        term 2 {
            from protocol bgp;
            then reject;
        }
    }
    condition route1 if-route-exists 1.129.0.1/32 table inet.0;
}

This policy (which can be used _only_ as BGP export policy) accepts 1.129/16 aggregate route _only_if_ 1.129.0.1/32 route exists in inet.0 table.

HTH

Regards

Alex

Thank you very much Alex

You say "thanks" to Alex but you give yourself the "accepted solution"?

And you don't even give him a kudo for helping you through a sticky configuration issue?

By the way "accepted solutions" that you give yourself are not counted towards your community standing anyway, so give them where they are earned.

Kudos to Alex for the real solution.