From: ccie2002@bellsouth.net
Date: Mon May 23 2005 - 21:48:41 GMT-3
Hello:
I have a ADSL connection running PPPOE with a dialer interface on a Cisco
2600 router with 12.2 IOS connecting to Bell South
The problem I am seeing is that when I turn on ethereal and sniff
the traffic on my LAN going out on the ADSL connection
I am seeing a loopback on the mac address for my protocol.
The protocol type is loopback with 0x9000.
I still can reach the internet even with this loopback seen so I do not know
why I am seeing a loop on ethereal sniffing the traffic
going out on the WAN.
I ran a tcp dump on the same connection and I do not
see any problems with this. Does anyone know why I might
be seeing the protocol loop on my ethereal when sniffing the traffic.
Is there something I need to configure in my router
to stop this from occurring. Please note, I took all devices off
the LAN and left just my laptop (ip 10.10.10.4) and
my router (10.10.10.1) and the problem was still there.
I was seeing the same source and designation for my
mac address of my ethernet interface in my router.
(10.10.10.1)
I did not include the ethereal snapshots as it is a cap file and not sure how
to put the cap file in txt format.
Rack1R5#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.10.10.1 - 0010.7b1c.a220 ARPA Ethernet0/0
Internet 10.10.10.6 6 000d.9d84.05a4 ARPA Ethernet0/0
Internet 10.10.10.4 1 000d.608e.4ab6 ARPA Ethernet0/0
Internet 10.10.10.5 6 000c.411b.4405 ARPA Ethernet0/0
Below shows I can stil reach the internet
Rack1R5#ping cisco.com
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.25, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 108/109/112 ms
Rack1R5#
TCP dump below shows nothing
linux:/home/cisco# tcpd -i eth0
linux:/home/cisco #
Configs of router below
version 12.2
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname "Rack1R5"
!
logging buffered 4096 debugging
!
username XXXXXX@bellsouth.net password XXXXXX
ip subnet-zero
!
!
ip name-server 205.152.37.23
ip name-server 205.152.132.23
ip dhcp excluded-address 192.168.1.2
ip dhcp excluded-address 10.10.10.1
ip dhcp excluded-address 205.152.37.23
ip dhcp excluded-address 205.152.132.23
!
ip dhcp pool DHCP
network 192.168.1.0 255.255.255.0
default-router 192.168.1.2
!
ip dhcp pool TEST
network 10.10.10.0 255.255.255.0
default-router 10.10.10.1
dns-server 205.152.132.23
lease infinite
ip cef
vpdn enable
!
vpdn-group pppoe
request-dialin
protocol pppoe
!
ip cef
vpdn enable
!
vpdn-group pppoe
request-dialin
protocol pppoe
!
interface ATM0/0
bandwidth 384
no ip address
load-interval 30
no atm ilmi-keepalive
dsl operating-mode ansi-dmt
!
interface ATM0/0.100 point-to-point
pvc 8/35
cbr 384
pppoe-client dial-pool-number 1
interface Ethernet0/0
ip address 10.10.10.1 255.255.255.0
ip nat inside
ip nbar protocol-discovery
load-interval 30
half-duplex
interface Dialer1
ip address X.X.X.X 255.255.255.0
ip access-group 160 in
ip accounting output-packets
ip mtu 1492
ip nat outside
ip nbar protocol-discovery
encapsulation ppp
dialer pool 1
dialer idle-timeout 0
ppp authentication chap callin
ppp chap hostname XXXXXXX@bellsouth.net
ppp chap password XXXXXXX
This archive was generated by hypermail 2.1.4 : Fri Jun 03 2005 - 10:12:00 GMT-3