RE: Policy routing not matching ICMP in the counters?

From: Ben Holko (ben.holko@datacom.com.au)
Date: Thu Aug 16 2007 - 19:43:36 ART


I had considered this, but it doesn't explain it

Also it's not local policy, as the pings and traces are coming from a
remote router, not from the router which is doing the policy routing

Any other thoughts?

Ben

From: eicc tester [mailto:reto_ccie@yahoo.com]
Sent: Friday, 17 August 2007 6:28 AM
To: Ben Holko; ccielab@groupstudy.com
Subject: Re: Policy routing not matching ICMP in the counters?

Please consider the fact that ping are base on icmp packet only, instead
traceroute may use UDP packet on port 33434 to sent in order to see the
unreachables back.

just consider the fact that may be not the same behavior of traceroute
and ping.

Ben Holko <ben.holko@datacom.com.au> wrote:

        Hey all,

        Consider the following policy routing config:

        ip access-list extended IP_PHONES
        permit ip 10.89.8.0 0.0.1.255 10.100.57.0 0.0.0.255
        permit ip 10.89.72.0 0.0.1.255 10.100.57.0 0.0.0.255
        !
        route-map IP_PHONES permit 5
        match ip address IP_PHONES
        set ip next-hop 10.89.71.4
        !
        route-map IP_PHONES permit 10
        !

        And I apply policy routing on selected interfaces with "ip
policy
        route-map IP_PHONES"

        The policy routing appears to be working when I test from the
relevant
        subnet, but "show route-map" fails to include pings in the
counters, but
        traceroute does increase the counters:

        Router1#show route-map
        route-map IP_PHONES, permit, sequence 5
        Match clauses:
        ip address (access-lists): IP_PHONES
        Set clauses:
        ip next-hop 10.89.71.4
        Policy routing matches: 9 packets, 540 bytes <----this does not
        increase with ping traffic, but it goes up with traceroute
packets
        route-map IP_PHONES, permit, sequence 10
        Match clauses:
        Set clauses:
        Policy routing matches: 16 packets, 1539 bytes <---- this does
not go
        up with ping packets either
        Router1#

        "debug ip policy" fails to show anything for the ICMP packets,
but does
        show the traceroute packets being policy routed

        Router1#debug ip policy

        Router2#ping 10.100.57.1 source 10.89.8.2

        Type escape sequence to abort.
        Sending 5, 100-byte ICMP Echos to 10.100.57.1, timeout is 2
seconds:
        Packet sent with a source address of 10.89.8.2
        !!!!!
        Success rate is 100 percent (5/5), round-trip min/avg/max =
1/1/1 ms
        Router2#

        Router2#traceroute
        Protocol [ip]:
        Target IP address: 10.100.57.1
        Source address: 10.89.8.2
        Numeric display [n]:
        Timeout in seconds [3]:
        Probe count [3]:
        Minimum Time to Live [1]:
        Maximum Time to Live [30]:
        Port Number [33434]:
        Loose, Strict, Record, Timestamp, Verbose[none]:
        Type escape sequence to abort.
        Tracing the route to 10.100.57.1

        1 10.89.254.1 0 msec 0 msec 0 msec
        2 10.89.71.4 0 msec * *
        Router2#

        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
        d=10.100.57.1, len 28, policy match
        *Mar 1 01:07:12: IP: route map IP_PHONES, item 5, permit
        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
d=10.100.57.1
        (Vlan320), len 28, policy routed
        *Mar 1 01:07:12: IP: GigabitEthernet1/0/28 to Vlan320 10.89.71.4
        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
        d=10.100.57.1, len 28, policy match
        *Mar 1 01:07:12: IP: route map IP_PHONES, item 5, permit
        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
d=10.100.57.1
        (Vlan320), len 28, policy routed
        *Mar 1 01:07:12: IP: GigabitEthernet1/0/28 to Vlan320 10.89.71.4
        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
        d=10.100.57.1, len 28, policy match
        *Mar 1 01:07:12: IP: route map IP_PHONES, item 5, permit
        *Mar 1 01:07:12: IP: s=10.89.8.2 (GigabitEthernet1/0/28),
d=10.100.57.1
        (Vlan320), len 28, policy routed
        *Mar 1 01:07:12: IP: GigabitEthernet1/0/28 to Vlan320 10.89.71.4
        Router1#

        Why isn't my PING traffic seemingly being policy routed?

        Ben



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