From: Mike Williams (ccie2be@swbell.net)
Date: Sat Jun 21 2003 - 23:54:29 GMT-3
But did you disable fast-switching on the ethernet interface? AFAIK,
you need to disable fast switching on the ingress interface if you want
a debug to work properly. (i.e. if you receive a packet on the ethernet
interface and it has fast switching enabled, then it bypasses the Route
Processor (and therefore debug) even if fast switching is disabled on
the serial, it won't help any if the packets you want to debug arrive on
the ethernet interface).
If you see the packets with a sniffer on a hub, then it's obvious it's
hitting the router. I would put the ethernet interface in process
switching mode (no ip route-cache, no ip route-cache cef) then try the
debug again.
Mike W.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jonathan V Hays
Sent: Saturday, June 21, 2003 4:17 PM
To: 'Volkov, Dmitry (IDS Canada)'; ccielab@groupstudy.com
Cc: wing_lam@jossynergy.com
Subject: RE: helper address
I did disable fast-switching on the serial interfaces. But the fast
switching issue does not explain why debug did not see ethernet segment
broadcasts that my PC sniffer did, when plugged into the same hub (not a
switch).
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of Volkov, Dmitry (IDS Canada)
> Sent: Saturday, June 21, 2003 3:14 PM
> To: 'Jonathan V Hays'; ccielab@groupstudy.com
> Cc: wing_lam@jossynergy.com
> Subject: RE: helper address
>
>
> Did You disable fast switching ?
> http://www.cisco.com/en/US/tech/tk801/tk379/technologies_tech_
> note09186a0080
> 17874c.shtml#debugippacket
>
> > -----Original Message-----
> > From: Jonathan V Hays [mailto:jhays@jtan.com]
> > Sent: Saturday, June 21, 2003 2:07 PM
> > To: ccielab@groupstudy.com
> > Cc: wing_lam@jossynergy.com
> > Subject: RE: helper address
> >
> >
> > Hi,
> >
> > You are right that "debug ip packet detail" seems a bit
> flaky in this
> > instance.
> >
> > I spent some time experimenting with "ip helper-address" myself,
> > generating DHCP Discover messages to be forwarded by the router to a
> > remote server. Not only did I not see the packets on the remote
> > segment, "debug ip packet detail" does not always see the DHCP
> > Discover broadcasts from the client on the LOCAL segment, even when
> > my PC sniffer
> > sees them. Hmmm. Strange ....
> >
> > Jonathan
> >
> > > -----Original Message-----
> > > From: wing_lam@jossynergy.com [mailto:wing_lam@jossynergy.com]
> > > Sent: Monday, June 23, 2003 11:15 AM
> > > To: Jonathan V Hays
> > > Cc: ccielab@groupstudy.com
> > > Subject: RE: helper address
> > >
> > >
> > >
> > > Hi Jonathan,
> > >
> > > I am generating UDP broadcast by port 2000 traffic in
> > > 192.168.1.0/24 subnet
> > > and I have used helper address and forward-protocol in the router:
> > >
> > > Host broadcast --> 192.168.1.1 router -- ATM p-to-p--
> > > 192.168.2.4 router
> > >
> > > My comand is ip helper-address 192.168.2.4 & ip
> > > forward-protocol udp 2000
> > >
> > > But when I "debug ip packet detail" in the 192.168.2.4
> > > router, I haven't
> > > see any packet comes.
> > >
> > > Should I able to see these helpered packets in 192.168.2.4
> > > router? or it's
> > > normal that I cannot see them?
> > >
> > > The following is my interface config
> > >
> > > interface FastEthernet0/0
> > > ip address 192.168.1.1 255.255.255.0
> > > ip helper-address 192.168.2.4
> > > ip directed-broadcast
> > > ip router isis DOG
> > > ip pim dr-priority 100
> > >
> > > Thx,
> > > BBD (Big Black Dog)
> > >
> > >
> > >
> > >
> > >
> > >
> > > "Jonathan V Hays"
> > >
> > >
> > > <jhays@jtan.com> To:
> > > <ccielab@groupstudy.com>
> > >
> > > cc:
> > > <wing_lam@jossynergy.com>
> > >
> > > 06/21/2003 11:05 Subject: RE:
> > > helper address
> > >
> > > PM
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> > > > Behalf Of wing_lam@jossynergy.com
> > > > Sent: Monday, June 23, 2003 5:23 AM
> > > > To: ccielab@groupstudy.com
> > > > Subject: helper address
> > > >
> > > >
> > > > Hi, Group;
> > > >
> > > > I would like to test the "ip helper" address function. I
> > > > generate a subnet broadcast in a interface and using helper
> > > > address to redircet this subnet
> > > > broadcast to another host, but no matter I do what debugging,
> > > > I cannot see
> > > > packet go to the host; anybody please suggest a testing
> > > > method on whether
> > > > the helper address config is success.
> > >
> > >
> > > Please be more specific. Given the sketchy information you
> > > have provided
> > > we would have to do a LOT of guessing to figure out what you
> > > are doing.
> > >
> > > 1. Post your config.
> > >
> > > 2. Describe the topology.
> > >
> > > 3. Describe exactly what you are doing to test. How are you
> > generating
> > > the broadcast? On what machine? Another router? What kind
> > of broadcast
> > > are you generating? What debug command are you using and
> > where are you
> > > using it?
> > >
> > > Note that the "ip helper-address" forwards specific
> > broadcasts for the
> > > eight UDP destination ports below:
> > >
> > > 37 time server
> > > 49 TACACS
> > > 53 DNS
> > > 67 BOOTP/DHCP Server
> > > 68 BOOTP/DHCP Client
> > > 69 TFTP
> > > 137 NETBIOS Name Service
> > > 138 NETBIOS Datagram Service
> > >
> > > So if you are testing the helper-address command you will have to
> > > generate one of those types of broadcasts.
> > >
> > http://www.cisco.com/univercd/cc/td/doc/product/software/ios12
> > 2/122cgcr/
> > fipras_r/1rfipadr.htm#1018608
> >
> > HTH
> >
> >
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