Interfaces FE on Cisco 2821 problem

Discussion in 'Cisco' started by Merv, Oct 3, 2005.

  1. Merv

    Merv Guest

    You have an FastEthernet switching module for which all of the port are
    layer 2.

    If you want layer 3 Fast Ethernet ports you will have to get a
    diffeenthardware for the 2821.

    With respect to the VLAN interface and the Fast Ethernet port, you will
    need to plug a device into the Fast Ethernet port before the VLAN
    interface will come up. Check by using show interface command and
    making sure the VLAN interfce shows as up and up BEFORE trying to ping
    it.
     
    Merv, Oct 3, 2005
    #1
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  2. Merv

    Merv Guest

    You could assign each of the 8 FE ports to a differnet VLAN thereby
    allowing you to use up to 8 differnet IP addresses.

    Where are you trying to ping the IP address 1`92.168.0.1 from ?
    - within the router (ie from the console port or from a router telnet
    session) or from an external device?

    Try pinging from console first, then telnet, then external
     
    Merv, Oct 3, 2005
    #2
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  3. Merv

    Merv Guest

    To ping from the console connect a PC to the console port usually a
    blue cable provided by Cisco.

    Enter the command "ping 192.168.0.1" at the router prompt
     
    Merv, Oct 3, 2005
    #3
  4. Merv

    Merv Guest

    Disable any firewall software running on the PC.


    Telnet to router and ping 192.168.0.2 and then dispaly the ARP cache by
    uisng the command show ip arp 192.168.0.2

    On the PC go to an command window, ping the IP address 192.168.0.1 and
    then issue command arp -a and see if you see the MAC address for the
    router port.
     
    Merv, Oct 3, 2005
    #4
  5. Merv

    Merv Guest

    Post the output of
    sh int fa 0/3/8
    sh int vlan 192


    So what you have learned is that ping (ICMP) is failing because neither
    the PC nor the router get an ARP reply from each other.

    To confirm, enable logging buffer and then the following debugs

    conf t
    logging buffer
    exit
    wri mem

    debug ip icmp
    debug arp

    then try to ping 192.168.0.2


    Load Etherreal onto the PC and see if it is receiving any ARP requests
    from the router.
     
    Merv, Oct 3, 2005
    #5
  6. Merv

    Merv Guest

    Also make sure that the PC's NIC and the switch port have the same
    duplex and speed settings ( ie both auto or both with same fixed value
    for duplex and speed).
     
    Merv, Oct 3, 2005
    #6
  7. Merv

    Merv Guest

    sorry, to see the debug output enter the command "show log"
     
    Merv, Oct 3, 2005
    #7
  8. Merv

    Merv Guest

    sorry, to see the router debug output enter the command "show log"
    BTW the other way of doing this is to configure logging monitor
    debugging and then enter the command terminal monitor, then you will
    see the debug output in real time

    I do not know linux so I cannot comment on the eth0 versus eth1.

    Do you have a Windows PC that you can connect to the router port ?
     
    Merv, Oct 3, 2005
    #8
  9. Merv

    Merv Guest

    What the last test showed you is that you Linux PC is receiving an ARP
    request form the router, perhaps the Linux PC is sending the ARP reply
    to the wrong logical/physical interface ??? Does the Linux box have
    multiple NICs in it ?
     
    Merv, Oct 3, 2005
    #9
  10. Merv

    Merv Guest

    ie did you config the IP address 192.168.0.2 on thelinux box interface
    that is connected to the Cisco router ???
     
    Merv, Oct 3, 2005
    #10
  11. Merv

    Bartosz Piec Guest

    Hello,

    I have a Cisco 2821 router. It has 2 GigabitEthernet interfaces and 8
    FastEthernet interfaces. But FE interfaces don't allow for assigning
    them IP addresses ("IP addresses may not be configured on L2 links.").
    Is there any possibility to do this? Other words - I want them to behave
    the same as GE.

    And the second thing. Trying to walkaround this, I made a VLAN, assigned
    it an IP address and make one of FE interefaces a member of it. I was
    hoping that, when I ping that address, the answer will be from the
    assigned interface. But it wasn't happen (there was no ping reply). Is
    this correct behaviour? And if yes, what is the reason for assigning an
    IP address for VLAN?
     
    Bartosz Piec, Oct 3, 2005
    #11
  12. Merv

    Bartosz Piec Guest

    So I can't have more than two interfaces with IP addresses?
    But the interface is up. It is like that:

    ....
    FastEthernet0/3/8 unassigned YES unset up
    up
    ....
    Vlan192 192.168.0.1 YES TFTP up
    up

    And the configuration:
    interface FastEthernet0/3/8
    switchport access vlan 192
    no ip address
    !
    interface Vlan192
    ip address 192.168.0.1 255.255.255.0
    ip nat inside
    !
     
    Bartosz Piec, Oct 3, 2005
    #12
  13. Merv

    Bartosz Piec Guest

    And connecting PC to one of that port it will be allow to ping that
    interface?
    I have a PC connected to the FE 0/3/8 interface and I'm using ping on it.
    I don't understand how to ping from the console.
     
    Bartosz Piec, Oct 3, 2005
    #13
  14. Merv

    Bartosz Piec Guest

    I can ping it when I telnet to the router:

    xxx#ping 192.168.0.1

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 192.168.0.1, timeout is 2 seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

    But when I connect a PC with 192.168.0.2 address to the FE 0/3/8 port,
    it can't ping 192.168.0.1.
     
    Bartosz Piec, Oct 4, 2005
    #14
  15. Merv

    Bartosz Piec Guest

    There isn't any firewall.
    Protocol Address Age (min) Hardware Addr Type Interface
    Internet 192.168.0.2 0 Incomplete ARPA

    So the ARP couldn't determine the MAC address of 192.168.0.2?
    The same:
    ? (192.168.0.1) at <incomplete> on eth1
     
    Bartosz Piec, Oct 4, 2005
    #15
  16. Merv

    Bartosz Piec Guest

    FastEthernet0/3/8 is up, line protocol is up
    Hardware is Fast Ethernet, address is 0013.808a.8be8 (bia 0013.808a.8be8)
    MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation ARPA, loopback not set
    Keepalive set (10 sec)
    Full-duplex, 100Mb/s
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 03:38:00, 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: 0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    5571 packets input, 522914 bytes, 0 no buffer
    Received 5043 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
    0 input packets with dribble condition detected
    12233 packets output, 945178 bytes, 0 underruns
    0 output errors, 0 collisions, 3 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out
    Vlan192 is up, line protocol is up
    Hardware is EtherSVI, address is 0012.80b6.5538 (bia 0012.80b6.5538)
    Internet address is 192.168.0.1/24
    MTU 1500 bytes, BW 100000 Kbit, DLY 1000000 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 00:00:08, 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: 0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    5458 packets input, 491443 bytes, 0 no buffer
    Received 5458 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
    5474 packets output, 418931 bytes, 0 underruns
    0 output errors, 1 interface resets
    0 output buffer failures, 0 output buffers swapped out
    Yes, now I know that.
    Nothing happens. No debug output is displayed. I also tried to ping
    router from PC.
    I have linux on that machine with no GUI. But I started a tcpdump
    (tcpdump arp) and get this output:

    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
    17:10:02.502660 arp who-has 192.168.0.2 tell rtr-ipbx01.f1.pl
    17:10:02.504015 arp reply 192.168.0.2 is-at 00:11:43:d9:83:7b

    But the ifconfig looks like this:
    ....
    eth1 Link encap:Ethernet HWaddr 00:11:43:D9:83:7C
    inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0

    Why eth0 gets the ARP requests? eth1 has no ARP entries in tcpdump.
     
    Bartosz Piec, Oct 4, 2005
    #16
  17. Merv

    Neil Cherry Guest

    You probably have the cables in the wrong port on your Linux box or do
    you have the same IP address on both eth0 & eth1? The above arp
    suggests that eth0 (00:11:43:d9:83:7b) is responding to 192.168.0.2
    but the ifconfig says eth1 also has the same IP. Looks like your doing
    something strange.
     
    Neil Cherry, Oct 4, 2005
    #17
  18. Merv

    xcwillix Guest

    Is you Linux box doing any bridging or routing ??

    It looks like too me your traffic on eth1 trying to use eth0 to get to
    the router.

    Thats just a guess ... would need more info. ie

    Linux Box run and display output

    netstat -r

    ifconfig -a
     
    xcwillix, Oct 4, 2005
    #18
  19. Merv

    Bartosz Piec Guest

    Neil Cherry napisa³(a):
    Yes, exactly. I was connecting cable to the one computer, but
    configuring the other. Shame on me and my boss (who gave me that
    computer as the correct one)... I realized this after using mii-tool.
     
    Bartosz Piec, Oct 4, 2005
    #19
  20. Merv

    Cen Guest

    Sure. You put the ports in "routed mode".
    Example:
    int fa0/0
    no switchport
    ip address 10.1.1.1 255.255.255.0
    etc. . . .
     
    Cen, Oct 4, 2005
    #20
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