[c-nsp] Missing 'packet-too-big' ICMPs on 12.2(28)SB6

[Karol Mares]

Hi,

On 9/10/07, Gerald Krause <gk at ax.tc> wrote:
>
> Gerald Krause wrote:
> > Hi,
> >
> > I have a 7206VXR as LNS under 12.2(28)SB6 and wonder if anyone
> > experience a strange ICMP behaviour regarding fragmentation/MTU
> > bounderies. It seems that the router doesn't generate appropriate
> > ICMP messages when pakets arrive that the system can't (or isn't
> > allow to) fragment.
> >
> > The only problem with our config could be the fact that we have
> > configured a MTU of 1530 byte (because of MPLS) on the FEs. But even
> > if this could be problematic I would expect that in the case that a
> > paket arrive which can't be delivered through the VirtualInterfaces
> > (MTU 1448 byte) the system have to mention that in the logging buffer.
> > Thats why I have enabled ICMP debugging and related CEF debugging
> > but I never see 'packet-too-big' ICMP messages, only 'echo' and
> > 'host/port unreachable' messages are logged. But I See that CEF is
> > aware of the fact that it can't deliver the packet without
> > fragmentation:
> >
> >
> > debug:
> > ======
> > Generic IP:
> >   ICMP packet debugging is on
> > IP CEF:
> >   IP CEF drops debugging is on
> >     for access list 80
> >   IP CEF fragmentation debugging is on
> >


Curious, can you show me the show int fa<x> and show ip traffic  command ?

Thanks

--
         iso