Official Lammle User Forum

alabedekenny · #1 09-01-2010, 12:50 PM

Hello...

I had a "funny" but serious experience today at a client's office. I had configured an 1811 wireless router, only to go and install. But there, I could NOT ping the Ethernet interface of the VSAT Modem.

The IP addresses were correctly configured and both interfaces were in the same subnet. I even configured the same speed (auto/full duplex) on both interfaces, used both straight through and cross-over cables, all to no avail.

Please can somebody help me? I want a solution to this issue. I configured the same subnet on my laptop and plugged directly to the Modem, and it worked perfectly. But its not working with the 1811 ISR FastEthernet 0 interface.

Could it be an encapsulation mismatch? The router in use presently is a Mikrotik router and its working fine.

Please help me out!
Thanks for your usual useful contributions.

lammle · #2 09-01-2010, 01:35 PM

Can you ping the 1811 F0 interface from the console?
Do you plug the modem into a switch and the switch into the router?
If so they are straight-through, if not, crossover.
If you are using a switch, make sure both ports are in the same VLAN
Todd Lammle

Big Evil · #3 09-01-2010, 01:55 PM

Can you see the modem in the arp cache on the router?
Do a show ip int brief, is the port up/up etc..

alabedekenny · #4 09-02-2010, 04:18 AM

TL....
1. I can ping the 1811 Fa0 from thee console, i can even ping it from my laptop which is in another subnet on the 1811 Fa1.
2. I did plug the modem to a switch (2960) and the switch to the router...all the ports on the switch are in vlan 1 except the Gi0/1 uplink to the router. but I will try plug the router to an access port and see what will happen.
3. I used both straight through and cross over cables, both didn't work.

BE....
1. Thanks for that idea...I didnt check the arp catch of the router, but will do that this morning...can't really remember how to do that, can you remind me?
2. Funny enough, I didn't check if the interface is up/up.

Thanks a lot TL and BE....Im almost on my way now, I'll check all those issues and give you the report when I come back....THANKS!

alabedekenny · #5 09-02-2010, 11:24 AM

Back!...but this is getting interesting...and confusing.
See the tests I did in two folds.

Please note:
Router Fa0 IP - 81.199.160.100/29
Modem interface - 81.199.160.97/29

1.(a). I connected the Router Fa0 to modem with STRAIGHT-THROUGH CABLE
show ip interface brief, int fa0 is up/up.
Ping router fa0/0 (81.199.160.100) - 0% (not successful)
Ping modem (81.199.160.97) - 0% (not successful)

show arp....see the result
ROUTER-MODEM WITH STRAIGHT THROUGH CABLE
Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 6 000b.a403.15b0 ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0

1.(b). I connected the Router Fa0 to modem with CROSS-OVER CABLE
show ip interface brief, int fa0 is up/up.
Ping router fa0/0 (81.199.160.100) - 0% (not successful)
Ping modem (81.199.160.97) - 0% (not successful)

show arp....see the result
ROUTER-MODEM WITH CROSS-OVER CABLE
Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 1 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Then I repeated the same exercise but the result was inconsistent I think the problem is with the modem

Take a look at this:

ROUTER - MODEM STRAIGHT THROUGH CABLE
Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

ROUTER - MODEM CROSS-OVER CABLE
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.25.195 0 Incomplete ARPA
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1
Note the 172.16.24.195...is a strange address, no interface is configured on the router with that subnet.

Then later.....

Protocol Address Age (min) Hardware Addr Type Interface
Internet 78.38.250.66 0 Incomplete ARPA
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1
Internet 172.16.24.195 0 Incomplete ARPA

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

The modem keeps appearing and disappearing form the arp table.
Then some strange IP addresses also appearing and disappearing.
Note that only the modem, 2960 switch and my laptop are connected to the router. I dont know where all those strange IP addresses are coming from

I later connected the modem to the switch, and switch to the router...the result is similar...
NO PING WAS SUCCESSFUL, BOTH TO THE ROUTER FA0 INTERFACE AND THE MODEM.

THE RESULT OF THE CONNECTION MODEM-SWITCH-ROUTER IS PASTED BELOW:

MODEM-SWITCH-ROUTER FA0 STRAIGHT-THROUGH CABLE
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

LATER.........

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 0 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Internet 81.199.160.97 2 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

NOTE: without disconnecting anything, the age(time) of the modem reduced to 1 minute. I think it should be increasing...I dont understand this modem! see below:

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 1 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

MODEM-SWITCH-ROUTER FA0 CROSS-OVER CABLE
Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

LATER..

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.196.174.126 0 Incomplete ARPA
Internet 81.199.160.97 0 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Note the strange Ip addressn 81.196.174.126...???

Then later....

Internet 81.199.160.97 1 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 2 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 0 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 1 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

This is how far I could go because the client was rushing out...its getting more interesting but confusing...can you make anything out of this?

In all, no ping was successful from the router console....both to the router fa0 and modem interface.

Big Evil · #6 09-02-2010, 01:36 PM

It sounds like there is not route on either the modem or the router.
No idea why the arp cache is so odd though.
Can you post the config of the router and the modem?

alabedekenny · #7 09-06-2010, 09:21 AM

I cant access the modem, but the config of the router is pasted below. The problem is, there's no name on the modem. I cant find anything to trace the manufacturer...
I tried the sh arp again today, then came this very weird output:

SUPREME_ROUTER#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 0 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 58.221.32.117 0 Incomplete ARPA
Internet 81.199.160.97 1 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 2 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.176.230.16 0 Incomplete ARPA
Internet 81.176.230.27 0 Incomplete ARPA
Internet 81.176.230.28 0 Incomplete ARPA
Internet 81.199.160.97 3 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 117.79.92.41 0 Incomplete ARPA
Internet 117.79.92.44 0 Incomplete ARPA
Internet 130.117.190.204 0 Incomplete ARPA
Internet 130.117.190.207 0 Incomplete ARPA
Internet 130.117.190.213 0 Incomplete ARPA
Internet 130.117.190.216 0 Incomplete ARPA
Internet 202.177.216.233 0 Incomplete ARPA
Internet 202.177.216.236 0 Incomplete ARPA

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.176.230.16 0 Incomplete ARPA
Internet 81.176.230.27 0 Incomplete ARPA
Internet 81.199.160.97 3 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 117.79.92.41 1 Incomplete ARPA
Internet 130.117.190.210 0 Incomplete ARPA
Internet 130.117.190.213 0 Incomplete ARPA
Internet 130.117.190.216 0 Incomplete ARPA

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 4 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 4 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1
Internet 172.16.24.195 0 Incomplete ARPA

Protocol Address Age (min) Hardware Addr Type Interface
Internet 81.199.160.97 6 000b.a403.15b0 ARPA FastEthernet0
Internet 81.199.160.100 - d0d0.fdcd.9b0a ARPA FastEthernet0
Internet 172.16.1.1 - d0d0.fdcd.9b0b ARPA FastEthernet1

I wonder where these strange internet IP addresses are coming from. But I dont think there's a problem with the router, since the IP address of the router and the modem are in the same subnet, then they should ping, at least. Anyway...this is the router config:

crypto pki trustpoint TP-self-signed-4049932617
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-4049932617
revocation-check none
rsakeypair TP-self-signed-4049932617
!
!
crypto pki certificate chain TP-self-signed-4049932617
certificate self-signed 01

dot11 syslog
!
dot11 ssid ADMIN_WIRELESS
vlan 2
authentication open
mbssid guest-mode
!
ip source-route
!
!
ip dhcp excluded-address 192.168.3.1 192.168.3.15
!
ip dhcp pool LAN
import all
network 192.168.3.0 255.255.255.0
dns-server 81.199.3.7 81.199.3.18
default-router 192.168.3.1
!
!
ip cef
ip domain name yourdomain.com
ip name-server 81.199.3.7
ip name-server 81.199.3.18
no ipv6 cef
!
multilink bundle-name authenticated
!

crypto isakmp policy 1
encr 3des
authentication pre-share
group 2
!
crypto isakmp client configuration group ADMIN_STAFF
key sef_adm1n
pool SDM_POOL_1
group-lock
save-password
netmask 255.255.255.0
!
crypto isakmp client configuration group TEACHING_STAFF
key sef_teach1ng
pool SDM_POOL_2
group-lock
save-password
netmask 255.255.255.0
!
crypto isakmp client configuration group TECHNICAL
key sef_tech
pool SDM_POOL_3
max-users 10
netmask 255.255.255.0
crypto isakmp profile ciscocp-ike-profile-1
match identity group ADMIN_STAFF
match identity group TEACHING_STAFF
match identity group TECHNICAL
client authentication list ciscocp_vpn_xauth_ml_1
isakmp authorization list ciscocp_vpn_group_ml_1
client configuration address respond
virtual-template 1
!
!
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
!
crypto ipsec profile CiscoCP_Profile1
set security-association idle-time 10800
set transform-set ESP-3DES-SHA
set isakmp-profile ciscocp-ike-profile-1
!
!
crypto ctcp port 10000
archive
log config
hidekeys
!
!
bridge irb
!
!
!
interface Loopback0
ip address 172.17.1.1 255.255.255.0
!
interface Dot11Radio0
no ip address
!
encryption vlan 2 key 1 size 40bit 7 C7846CDFA6A6 transmit-key
encryption vlan 2 mode wep mandatory
!
broadcast-key vlan 2 change 30
!
!
ssid ADMIN_WIRELESS
!
mbssid
speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0
channel 2437
station-role root
!
interface Dot11Radio0.2
encapsulation dot1Q 2 native
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 spanning-disabled
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
!
interface Dot11Radio1
no ip address
!
encryption vlan 2 key 1 size 40bit 7 1F6A7ED8DF3F transmit-key
encryption vlan 2 mode wep mandatory
!
broadcast-key vlan 2 change 30
!
!
ssid ADMIN_WIRELESS
!
mbssid
speed basic-6.0 9.0 basic-12.0 18.0 basic-24.0 36.0 48.0 basic-54.0
channel 5745
station-role root
no cdp enable
!
interface Dot11Radio1.2
encapsulation dot1Q 2 native
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 spanning-disabled
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
!
interface FastEthernet0
description $ETH-WAN$
ip address 81.199.160.100 255.255.255.248
ip access-group 100 in
ip access-group LAN_USERS out
ip nat outside
ip virtual-reassembly
speed auto
full-duplex
!
interface FastEthernet1
ip address 172.16.1.1 255.255.255.240
ip nat inside
ip virtual-reassembly
duplex auto
speed auto
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet4
switchport trunk native vlan 3
!
interface FastEthernet5
!
interface FastEthernet6
!
interface FastEthernet7
!
interface FastEthernet8
!
interface FastEthernet9
!
interface Virtual-Template1 type tunnel
ip unnumbered Loopback0
tunnel mode ipsec ipv4
tunnel protection ipsec profile CiscoCP_Profile1
!
interface Vlan1
description $ES_LAN$
ip address 172.16.20.1 255.255.255.0
bridge-group 1
!
interface Vlan2
no ip address
bridge-group 1
bridge-group 1 spanning-disabled
!
interface Vlan3
no ip address
bridge-group 1
!
interface Async1
no ip address
encapsulation slip
!
interface BVI1
ip address 192.168.3.1 255.255.255.0
ip nat inside
ip virtual-reassembly
!
ip local pool SDM_POOL_3 172.20.1.2 172.20.1.254
ip local pool SDM_POOL_2 172.19.1.2 172.19.1.254
ip local pool SDM_POOL_1 172.18.1.2 172.18.1.254
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 FastEthernet0
ip http server
ip http access-class 40
ip http authentication local
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
!
!
ip nat inside source list 1 interface FastEthernet0 overload
!
ip access-list standard LAN_USERS
remark CCP_ACL Category=1
permit 192.168.3.0 0.0.0.255
permit 172.16.1.0 0.0.0.255
!
ip access-list extended VPN_Remote
remark VPN Users Remote Login
remark CCP_ACL Category=4
permit ip 172.18.1.0 0.0.0.255 any
permit ip 172.19.1.0 0.0.0.255 any
permit ip 172.20.1.0 0.0.0.255 any
!
access-list 1 remark CCP_ACL Category=2
access-list 1 permit 192.168.3.0 0.0.0.255
access-list 1 permit 172.16.1.0 0.0.0.255
access-list 40 permit 192.168.3.0 0.0.0.15 log
access-list 40 permit 172.16.1.0 0.0.0.15 log
access-list 100 remark CCP_ACL Category=1
access-list 100 permit udp host 81.199.3.18 eq domain any
access-list 100 permit udp host 81.199.3.7 eq domain any
access-list 100 permit ip 192.168.3.0 0.0.0.15 any log
access-list 100 permit ip 172.16.1.0 0.0.0.15 any log
!
!
!
!
!
!
control-plane
!
bridge 1 protocol ieee
bridge 1 route ip

!
line con 0
password 7 122A27502D28232A
line 1
modem InOut
stopbits 1
speed 115200
flowcontrol hardware
line aux 0
line vty 0 4
access-class 40 in
transport input telnet ssh
line vty 5 15
access-class 40 in
transport input telnet ssh
!
end

Thanks always for your inputs.........

alabedekenny · #8 10-05-2010, 03:55 AM

poof!...
The modem was the problem. My client just changed their ISP and I integrated the 1811W, then....the network is working, PERFECTLY.

So the problem was with the former Modem...what a headache that thing gave me!
Thanks TL and BE for your useful contributions.

Big Evil · #9 10-05-2010, 12:15 PM

Awesome mate, glad your sorted.
When you don't managed all the kit you are working one eye shut.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
WLC - console and modem cable	crissa	Questions and Comments	1	02-16-2011 03:51 AM
Terminal Server - Modem	ynoadrive	CCNP Equipment	5	10-08-2010 04:41 AM
Wan switching	swaminathan	Switching	5	05-13-2010 03:47 AM
"encapsulation failed" incomplete ARP	Ray_Bcomplex	Internetworking	10	03-06-2010 08:03 AM
Question about WAN links	AndreasB	Chapter 16: WANs	2	06-03-2009 06:43 AM