No internet access from Cisco 1601R

Discussion in 'Cisco' started by Waltjones40, Jun 7, 2007.

  1. Waltjones40

    Waltjones40 Guest

    I can ping the Cisco router from the internet, I can even ping the
    Serial port from the internet, but connecting a cross over cable to my
    laptop, yields no internet. The T1 connection I inherited consists of
    a T1 line coming in to a Kentrox DataSmart 656. The DataSmart connect
    to the Cisco via an h54 serial cable.

    Here is a print out of the interfaces:
    Ethernet0 is up, line protocol is up
    Hardware is QUICC Ethernet, address is 00d0.58a3.76f0 (bia
    Description: connected to EthernetLAN
    Internet address is
    MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load
    Encapsulation ARPA, loopback not set, keepalive set (10 sec)
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 00:26:26, output 00:00:02, output hang never
    Last clearing of "show interface" counters never
    Queueing strategy: fifo
    Output queue 0/40, 0 drops; input queue 0/75, 0 drops
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    3154 packets input, 233310 bytes, 0 no buffer
    Received 8 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    0 input packets with dribble condition detected
    4666 packets output, 381927 bytes, 0 underruns
    0 output errors, 0 collisions, 2 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out
    Serial0 is up, line protocol is up
    Hardware is QUICC Serial
    Description: connected to Internet
    Internet address is
    MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load
    Encapsulation PPP, loopback not set, keepalive set (10 sec)
    LCP Open
    Listen: CDPCP
    Open: IPCP
    Last input 00:00:00, output 00:00:00, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0 (size/max/drops); Total output drops: 0
    Queueing strategy: weighted fair
    Output queue: 0/1000/64/0 (size/max total/threshold/drops)
    Conversations 0/2/256 (active/max active/max total)
    Reserved Conversations 0/0 (allocated/max allocated)
    5 minute input rate 1000 bits/sec, 1 packets/sec
    5 minute output rate 1000 bits/sec, 1 packets/sec
    12866 packets input, 765456 bytes, 0 no buffer
    Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
    5 input errors, 0 CRC, 5 frame, 0 overrun, 0 ignored, 0 abort
    12709 packets output, 700714 bytes, 0 underruns
    0 output errors, 0 collisions, 17 interface resets
    0 output buffer failures, 0 output buffers swapped out
    0 carrier transitions
    DCD=up DSR=up DTR=up RTS=up CTS=up

    Sending a ping to the DNS server yields this:
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to, timeout is 2
    Success rate is 0 percent (0/5)
    Waltjones40, Jun 7, 2007
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  2. I don't know if you made up the IP addresses you post, but none of
    them (including the "dns server") is pingable from here on the Net..
    Interfaces lookup, how about a routing table?
    So, you're talking at least layer-2 across the serial link upstream,
    but yet this IP doesn't seem routable on the general Net.

    Maybe your provider shut you down?
    Doug McIntyre, Jun 7, 2007
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  3. Waltjones40

    Waltjones40 Guest

    I can access the router from the Net. Here is the message:
    The server at level 15 access requires a username and

    Warning: This server is requesting that your username and password be
    sent in an insecure manner (basic authentication without a secure
    connection). The gateway address came from my ISP; and they told me
    today that the gateway address is wrong, it should be,
    to which I've changed it. also the "host" address is
    It is pingable.

    I'm good with Linksys, Netgear, low-end routers, this is my first
    experience with "high end" routers. I've figured out how to get in to
    this router, check it's config, but I'm not sure about checking its
    routing table. The static route is on Ser0. I have no idea
    what to add; so, I've left it at the default entry.
    Waltjones40, Jun 8, 2007
  4. Waltjones40

    Waltjones40 Guest

    Sorry about the two replies. Here is a list of the show route-map
    OutputCommand base-URL was: /level/15/exec/-
    Complete URL was: /level/15/exec/-/show/route-map/CR
    Command was: show route-map

    Nothing there. What do I do now? (I'll keep looking...)
    Waltjones40, Jun 8, 2007
  5. Hmm, okay, so you're trying a web-browser and you didn't supply the
    correct enable password? Try telnet instead. The web-interface is
    non-existant/barely there. These boxes were designed for CLI access only.
    "high end"??? At the time this router was made far far ago, this was
    the entry-model version only made to say they had something that was
    "cost effective". Its far from high-end.

    To see the routing table, 'show ip route'.

    A config with passwords removed would probably be good 'show conf'.
    Doug McIntyre, Jun 9, 2007
  6. Waltjones40

    Waltjones40 Guest

    Sorry about the high end remark. I've just nevery used a router like
    this before, and if I had a choice, wouldn't now... Anyway, show IP
    Route produced the following: is variably subnetted, 3 subnets, 3 masks
    C is directly connected, Serial0
    C is directly connected, Serial0
    C is directly connected, Ethernet0
    S* is directly connected, Serial0

    Show conf produced this:

    Using 833 out of 7506 bytes
    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    no service password-encryption
    hostname Cisco1600
    enable secret 5 $1$O3Dp
    ip subnet-zero
    ip name-server
    interface Ethernet0
    description connected to
    ip address
    no ip directed-broadcast
    interface Serial0
    description connected to Internet
    ip address
    no ip directed-broadcast
    encapsulation ppp
    router rip
    version 2
    passive-interface Serial0
    no auto-summary
    ip classless
    ip route Serial0
    ip http server
    snmp-server community public RO
    snmp-server location Phone Room
    line con 0
    exec-timeout 0 0
    password plaza
    transport input none
    line vty 0 4
    password *****

    I thing the problems are with the serial address and the ip
    classless settings.
    Waltjones40, Jun 11, 2007
  7. Waltjones40


    woah.. quick type no ip http server!!!
    and you can change your password now too.
    , Jun 11, 2007
  8. Waltjones40

    Scott Perry Guest

    Sorry about the high end remark. I've just nevery used a router like

    Cisco routers are very popular for a reason. The learning curve involved is
    frustrating like any required learning, but you receive greater device
    capibilities in return. Nothing in this problem/solution is really specific
    to Cisco technologies except having to interact with the Cisco IOS to
    resolve the problem. The problem looks to be more of a LAN communication
    problem. I have to guess it is IP address related because we can see the
    configuration file and test that the outside IP address of the router is
    communiting properly. What remains is how the host computer is configured
    to connect through this router to the Internet.

    I will gladly provide a command breakdown of your configuration:
    The router will put the device uptime in the "show logging" output. I
    personally prefer the current date and time as set by the "clock set ?"
    command instead of trying to figure out at what time the device was up for X
    hours and X minutes for a log entry. The commands "service timestamps debug
    datetime" and "service timestamps log datetime" will change that, if

    The hostname is set and the prompt shows the devicename. This section
    includes your enable mode password, a command to allow the new style of
    subnetting, and a DNS server to use for lookups from the router itself, not
    necessarily the hosts connecting from inside of the router.
    Simple enough. The inside LAN IP address range is between
    and You will notice that this is a 10mb/s connection, very
    possibly half-duplex due to the interface being "Ethernet" in Cisco
    terminology instead of "FastEthernet" (100mb/s) or "GigabitEthernet".

    Host computers connecting on this LAN segment, even on a crossover cable,
    will need to use an IP address in the range specified above with a subnet
    mask the same as specified above. The default gateway used by the host
    computers will be the IP address of the Ethernet0 interface on the Cisco
    I will include commands below to configure DHCP on this Cisco router for LAN
    use, just like the home brand equipment like SMC, DLink, and Linksys.
    Simple enough. Your router has a serial line connecting to an external
    CSU/DSU, so no additional configuration is needed than supplying the layer 3
    protocol (using an IP address) and the layer 2 protocol (PPP instead of HDLC
    or frame-relay or ATM). The DS-1 (T1) line has an IP address range between and which yields only two IP addresses - for you and for the ISP router upstream.
    This is dynamic routing, RIP style, as opposed to EIGRP or OSPF or the
    others. If your had other routers downstream in your network, information
    on available networks including the Internet would be passed between
    routers. It does not sound like you have any so this section of the
    configuration is not needed.
    I do not like the "network" command and would prefer that it was
    "network", but it still works.
    The line "ip route Serial0" means to send any default route
    traffic through interface serial 0. A default route is commonly expressed
    as subnet IP address with a subnet mask of Without this
    command, your router would not know which way to send network traffic bound
    for "default", a.k.a. anything not otherwise specified.
    Use the IOS command "show ip route" to see IP address range routing
    information. It shows how the LAN network is known, the WAN network to the
    ISP (all two usable addresses) is known, and anything that doesn't fall into
    those categories is "default" and falls under that line which looks
    something like "S* [1/0] via Serial0".
    This remaining sections specifies SNMP information and information about
    logging into the router on VTY ports via telnet or the console port.
    Your SNMP community string is set to the word "public" which is a commonly
    known setting. I strongly suggest prohibiting that by some means - a "no
    snmp-server community public RO" command in configuration mode would do
    No, those are not the cause. Internet communication on the serial interface
    is fine. Default routing is fine.

    LAN connectivity has not been covered by this troubleshooting. What IP
    addresses were you using on this computer connected by a crossover cable to
    the router? Private IP address ranges (10.X.X.X / 172.16-31.X.X /
    192.168.X.X) will not work. Here is the sample configuration for enabling a
    DHCP server on your Cisco router. Enter these commands in configuration

    ip dhcp pool lan-dhcp-pool
    dns-server address
    ip dhcp excluded-address

    The IP address used by hosts in this LAN will be global Internet IP
    addresses and have no firewall between them and the Internet. I strongly
    suggest putting a good access-list on this router for filtering inbound
    network traffic or enabling features on the hosts to protect themselves from
    Internet threats. Lucky you! You have five usable static Internet IP
    addresses! Go put up a web server... or something. :)

    Scott Perry
    Indianapolis, Indiana
    Scott Perry, Jun 11, 2007
  9. Waltjones40

    Waltjones40 Guest

    I just wanted to thank everyone who helped me with this project. The
    router is working fine, the T1 connection is great, etc. Thank you for
    taking time and helping me survive this mess.

    Waltjones40, Jun 18, 2007
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