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Community Member

Cisco 877 Issue - Could be Nat?

Hi

I'm setting up a VDSL/ADSL2+ DSLAM in test lab. I'm using a Cisco877 to test out the intial config. The 877 can connect and sync however it cant ping any devices on the DLSAM network .The CISCO877 is configured to use NAT and i think NAT is the issue here. Its has been sometime since i configured NAT and  i'm sure it is something relativility simple.

DSLAM network is 10.3.1.x

CISCO877 Internal network 192.168.99.x

Config of the CISCO877

version 12.4
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
!
!
dot11 syslog
ip source-route
!
!
ip cef   
ip domain name comtek.co.uk
!
!
!
!
!
!
!
archive
log config
  hidekeys
!
!
!
bridge irb
!
!
interface ATM0
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
no atm ilmi-keepalive
dsl enable-training-log
!
interface ATM0.1 point-to-point
description DSL Link
ip virtual-reassembly
atm route-bridged ip
pvc 8/35
  encapsulation aal5snap
!
bridge-group 1
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface Vlan1
ip address 192.168.99.1 255.255.255.0
ip nat inside
ip virtual-reassembly
!
interface BVI1
ip address 10.3.1.12 255.255.255.0
ip nat outside
ip virtual-reassembly
!
no ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 10.3.1.1
no ip http server
no ip http secure-server
!
ip nat inside source list 101 interface BVI1 overload
!
access-list 101 permit ip 192.168.99.0 0.0.0.255 any
!
!
!
!
control-plane
!
bridge 1 protocol ieee
bridge 1 route ip
!        
line con 0
no modem enable
line aux 0
line vty 0 4
login
!
scheduler max-task-time 5000
end

Router#sh arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.3.1.1                0   0018.19f3.f3e2  ARPA   BVI1
Internet  10.3.1.12               -   0000.0caa.8871  ARPA   BVI1
Internet  10.3.1.217              1   0024.d7e8.8624  ARPA   BVI1
Internet  10.3.1.250              2   0000.39a9.4fc6  ARPA   BVI1
Internet  192.168.99.1            -   001c.b1ec.0c62  ARPA   Vlan1
Router#ping 10.3.1.1

Sending 5, 100-byte ICMP Echos to 10.3.1.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5) Sending 5, 100-byte ICMP Echos to 10.3.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

Everyone's tags (1)
3 REPLIES
Hall of Fame Super Bronze

Cisco 877 Issue - Could be Nat?

If you can't ping from the BVI interface to the local device, it's not a NAT issue.

Verify the ATM is working and the BVI interface is up/up.

Community Member

Cisco 877 Issue - Could be Nat?

All interfaces seem to be up

*Mar 14 20:00:31.180: %SYS-5-CONFIG_I: Configured from console by consoleint

ATM0 is up, line protocol is up

  Hardware is MPC ATMSAR (with Alcatel ADSL Module)

  MTU 4470 bytes, sub MTU 4470, BW 852 Kbit/sec, DLY 430 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ATM, loopback not set

  Encapsulation(s): AAL5  AAL2, PVC mode

  10 maximum active VCs, 1024 VCs per VP, 1 current VCCs

  VC Auto Creation Disabled.

  VC idle disconnect time: 300 seconds

  Last input 00:00:00, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: Per VC Queueing

  5 minute input rate 0 bits/sec, 1 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     2980 packets input, 393968 bytes, 0 no buffer

     Received 716 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     957 packets output, 45411 bytes, 0 underruns

     0 output errors, 0 collisions, 2 interface resets

     97 unknown protocol drops

     0 output buffer failures, 0 output buffers swapped out

ATM0.1 is up, line protocol is up

  Hardware is MPC ATMSAR (with Alcatel ADSL Module)

  Description: DSL Link

  MTU 4470 bytes, BW 852 Kbit/sec, DLY 430 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ATM

     2391 packets input, 362274 bytes

     964 packets output, 45740 bytes

     0 OAM cells input, 0 OAM cells output

  AAL5 CRC errors : 0

  AAL5 SAR Timeouts : 0

  AAL5 Oversized SDUs : 0

  ARP type: ARPA, ARP Timeout 04:00:00

  Last clearing of "show interface" counters never

BVI1 is up, line protocol is up

  Hardware is BVI, address is 0000.0c1d.a3bd (bia 001a.e3b0.4e69)

  Internet address is 10.3.1.12/24

  MTU 4470 bytes, BW 4608 Kbit/sec, DLY 5000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input never, output never, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/0 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     315 packets input, 26026 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     31 packets output, 1860 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 unknown protocol drops

     0 output buffer failures, 0 output buffers swapped out

Router#sh arp

Protocol  Address          Age (min)  Hardware Addr   Type   Interface

Internet  10.3.1.12               -   0000.0c1d.a3bd  ARPA   BVI1

Internet  10.3.1.217              1   0024.d7e8.8624  ARPA   BVI1

Internet  192.168.99.1            -   001a.e3b0.4e69  ARPA   Vlan1

*Mar 14 20:00:31.180: %SYS-5-CONFIG_I: Configured from console by consoleint
ATM0 is up, line protocol is up
  Hardware is MPC ATMSAR (with Alcatel ADSL Module)
  MTU 4470 bytes, sub MTU 4470, BW 852 Kbit/sec, DLY 430 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ATM, loopback not set
  Encapsulation(s): AAL5  AAL2, PVC mode
  10 maximum active VCs, 1024 VCs per VP, 1 current VCCs
  VC Auto Creation Disabled.
  VC idle disconnect time: 300 seconds
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: Per VC Queueing
  5 minute input rate 0 bits/sec, 1 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     2980 packets input, 393968 bytes, 0 no buffer
     Received 716 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     957 packets output, 45411 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     97 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out
ATM0.1 is up, line protocol is up
  Hardware is MPC ATMSAR (with Alcatel ADSL Module)
  Description: DSL Link
  MTU 4470 bytes, BW 852 Kbit/sec, DLY 430 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ATM
     2391 packets input, 362274 bytes
     964 packets output, 45740 bytes
     0 OAM cells input, 0 OAM cells output
  AAL5 CRC errors : 0
  AAL5 SAR Timeouts : 0
  AAL5 Oversized SDUs : 0
  ARP type: ARPA, ARP Timeout 04:00:00
  Last clearing of "show interface" counters never
BVI1 is up, line protocol is up
  Hardware is BVI, address is 0000.0c1d.a3bd (bia 001a.e3b0.4e69)
  Internet address is 10.3.1.12/24
  MTU 4470 bytes, BW 4608 Kbit/sec, DLY 5000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/0 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     315 packets input, 26026 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     31 packets output, 1860 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out

Traffic seems to be coming down but not going up. The ARP table is populated with MACS on the 10.3.1.x network

Router#sh arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.3.1.12               -   0000.0c1d.a3bd  ARPA   BVI1
Internet  10.3.1.217              1   0024.d7e8.8624  ARPA   BVI1
Internet  192.168.99.1            -   001a.e3b0.4e69  ARPA   Vlan1

Hall of Fame Super Bronze

Cisco 877 Issue - Could be Nat?

.217 keeps showing up in your ARP table. Have you identified this device?

Can you ping it? You need to verify why .1 is not responding to pings.

If that device is owned by the ISP, you need to work with them.

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