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A couple of months ago I started having trouble getting to various sites including Amazon.com. It hasn't been too big a deal since I have access at work. It seems ...
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  1. #1
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    Linksys Adapter and Comcast


    A couple of months ago I started having trouble getting to various sites including Amazon.com. It hasn't been too big a deal since I have access at work. It seems there are more and more sites becoming unavailable though.

    Configuration: Clone box with Mandrake 9.1 and three linksys adapters; eth0 connects to a linksys router, eth1 connects to an apple extreme wireless router and eth2 connects to the comcast cable modem.

    So I brought down the cable modem and connected my Windows box directly to the modem. The Windows box has a MB based network chipset and it worked ok. I was able to get to Amazon and other sites. But I also noted that I had a completely different IP address.

    Last night I brought down the firewall and replaced eth2's adapter with one from my wife's computer, both Linksys. It was on a different network (a 71 address) as well and it couldn't see the gateway or resolve any hostnames.

    I brought it down again and pulled a card from my OpenBSD box, again a linksys and put it in the firewall and brought it back up. This time it had network access but it was on the same network as the first linksys card (67 network) and didn't have access to Amazon again.

    My next step is to pick up a non-linksys card and give it a try but I was curious if anyone else is experiencing a similar problem. I tried a search, both here and on Google but didn't find anything.

    Thanks.

    Carl

  2. #2
    Linux Enthusiast KenJackson's Avatar
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    Location
    Maryland, USA
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    Clone box with Mandrake 9.1 and three linksys adapters; eth0 connects to a linksys router, eth1 connects to an apple extreme wireless router and eth2 connects to the comcast cable modem.
    Is more than one of these adapters connected to an ISP? If yes, and yes intentionally, I can't help you.

    But in any case it would be interesting to see your routing table. Can you capture and post the output of this?
    $ netstat -nr

    Also, which of the interfaces is statically or dynamically (DHCP) configured? It would be interesting to see the contents of these files (they are all small):
    /etc/sysconfig/network
    /etc/sysconfig/network-scripts/ifcfg-eth0, ifcfg-eth1, ifcfg-eth2
    /etc/resolv.conf

    Finally, if you connect the Windows box to the cable modem (Comcast?) again, you might want to open a DOS window and run "ipconfig /all" and write down the last few lines, especially all the DNS servers. Then back on Linux, see if they are the same as the nameservers in /etc/resolv.conf and see if you can ping them.

    You've got a lot going on there with three adapters in one box. I would suspect the configuration, routing and DNS issues before I would suspect the hardware or an ISP.

  3. #3
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    Quote Originally Posted by KenJackson
    Is more than one of these adapters connected to an ISP? If yes, and yes intentionally, I can't help you.
    Nope. Just the one as indicated. The other two are internal networks.

    But in any case it would be interesting to see your routing table. Can you capture and post the output of this?
    $ netstat -nr
    I'll capture it tonight and assuming I can get through to here (I wasn't successful last night), I'll post it.

    Also, which of the interfaces is statically or dynamically (DHCP) configured? It would be interesting to see the contents of these files (they are all small):
    /etc/sysconfig/network
    /etc/sysconfig/network-scripts/ifcfg-eth0, ifcfg-eth1, ifcfg-eth2
    /etc/resolv.conf
    eth0 and 1 are static, eth2 is DHCP from comcast.

    Finally, if you connect the Windows box to the cable modem (Comcast?) again, you might want to open a DOS window and run "ipconfig /all" and write down the last few lines, especially all the DNS servers. Then back on Linux, see if they are the same as the nameservers in /etc/resolv.conf and see if you can ping them.
    The DNS servers are the same on both the Windows box and the Linux box.

    You've got a lot going on there with three adapters in one box. I would suspect the configuration, routing and DNS issues before I would suspect the hardware or an ISP.
    I did look at the routing table and it looked ok. DNS is able to resolve the sites but traceroute never gets to them. As I said in the first message, it's been working for a couple of years. This is coinciding with a message Comcast sent out a couple of months ago advising people that the DHCP information will be changing and that we should make sure we are using DHCP.

    Last year I rebuilt my old linux box (now the OpenBSD one) into a new one with mirrored drives, etc. Here's the image from the plan. The difference is that the ethernet adapters aren't the same. eth0 is 192.168.2.1, eth1 is 192.168.10.1 and eth2 is the comcast address (now different than the one in the diagram). There are two extra machines on the box now too. An OpenBSD one on the Linksys router and an XP laptop on the wireless network.



    If I can get here, I'll post additional info tonight.

    Thanks.

    Carl

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  5. #4
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    Ok, info:

    Code:
    [root@c-67-176-57-155 root]# netstat -rn
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
    192.168.2.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
    192.168.10.0    0.0.0.0         255.255.255.0   U         0 0          0 eth1
    67.176.56.0     0.0.0.0         255.255.248.0   U         0 0          0 eth2
    127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
    0.0.0.0         67.176.56.1     0.0.0.0         UG        0 0          0 eth2
    
    [root@c-67-176-57-155 sysconfig]# cat network
    NETWORKING=yes
    GATEWAY=""
    GATEWAYDEV=eth2
    HOSTNAME=x1-6-00-04-5a-75-92-af
    FORWARD_IPV4=true
    
    [root@c-67-176-57-155 network-scripts]# more ifcfg-eth0
    DEVICE=eth0
    BOOTPROTO=static
    IPADDR=192.168.2.1
    NETMASK=255.255.255.0
    NETWORK=192.168.2.0
    BROADCAST=192.168.2.255
    ONBOOT=yes
    MII_NOT_SUPPORTED=yes
    
    [root@c-67-176-57-155 network-scripts]# more ifcfg-eth1
    DEVICE=eth1
    BOOTPROTO=static
    IPADDR=192.168.10.1
    NETMASK=255.255.255.0
    NETWORK=192.168.10.0
    BROADCAST=192.168.10.255
    ONBOOT=yes
    MII_NOT_SUPPORTED=yes
    
    [root@c-67-176-57-155 network-scripts]# more ifcfg-eth2
    DEVICE=eth2
    BOOTPROTO=dhcp
    NETMASK=255.255.255.0
    ONBOOT=yes
    MII_NOT_SUPPORTED=yes
    NEEDHOSTNAME=yes
    
    [root@c-67-176-57-155 etc]# cat resolv.conf
    search hsd1.co.comcast.net.
    nameserver 68.87.69.146
    nameserver 68.87.85.98
    Here is the traceroute to amazon.com and other places I'm not able to get to.

    Amazon.com
    Code:
    [root@c-67-176-57-155 etc]# nslookup amazon.com
    Server:         68.87.69.146
    Address:        68.87.69.146#53
    
    Non-authoritative answer:
    Name:   amazon.com
    Address: 72.21.206.5
    Name:   amazon.com
    Address: 207.171.166.102
    
    [root@c-67-176-57-155 etc]# traceroute amazon.com
    traceroute: Warning: amazon.com has multiple addresses; using 207.171.166.102
    traceroute to amazon.com (207.171.166.102), 30 hops max, 38 byte packets
     1  * * *
     2  68.86.105.169 (68.86.105.169)  7.086 ms  12.738 ms  16.214 ms
     3  10g-9-1-ur02.arvada.co.denver.comcast.net (68.86.103.126)  7.167 ms  9.912 ms *
     4  10g-8-2-ar01.aurora.co.denver.comcast.net (68.86.103.41)  8.897 ms  7.784 ms *
     5  68.86.103.170 (68.86.103.170)  10.283 ms  10.097 ms  10.296 ms
     6  12.116.159.5 (12.116.159.5)  19.276 ms  9.866 ms  11.158 ms
     7  tbr1013801.dvmco.ip.att.net (12.123.207.138)  51.612 ms  35.957 ms  42.414 ms
     8  tbr2-cl31.sffca.ip.att.net (12.122.12.133)  33.974 ms  36.281 ms  33.153 ms
     9  ggr3-ge110.sffca.ip.att.net (12.122.82.169)  33.989 ms ggr3-ge90.sffca.ip.att.net (12.122.82.149)  47.174 ms  33.175 ms
    10  so1-3-0-2488M.ar1.SJC2.gblx.net (208.51.134.109)  34.688 ms  33.665 ms  33.661 ms
    11  pos7-0-0.10G.ar2.dca3.gblx.net (67.17.106.181)  80.686 ms  81.170 ms  88.894 ms
    12  146.82.32.82 (146.82.32.82)  81.840 ms  82.540 ms  82.627 ms
    13  * * *
    30  * * *
    Alternate address

    Code:
    [root@c-67-176-57-155 etc]# traceroute 72.21.206.5
    traceroute to 72.21.206.5 (72.21.206.5), 30 hops max, 38 byte packets
     1  * * *
     2  68.86.105.169 (68.86.105.169)  9.325 ms  16.099 ms  9.567 ms
     3  10g-9-1-ur02.arvada.co.denver.comcast.net (68.86.103.126)  7.306 ms  12.052 ms *
     4  10g-8-2-ar01.aurora.co.denver.comcast.net (68.86.103.41)  14.749 ms  9.427 ms  8.568 ms
     5  68.86.103.182 (68.86.103.182)  9.216 ms  8.426 ms  9.481 ms
     6  12.124.157.53 (12.124.157.53)  13.267 ms  8.589 ms  9.436 ms
     7  br2-a3120s4.dvmco.ip.att.net (12.127.4.158)  33.555 ms  32.873 ms  33.402 ms
     8  tbr1-p013501.dvmco.ip.att.net (12.122.1.30)  36.426 ms  34.818 ms  33.825 ms
     9  tbr2-cl31.sffca.ip.att.net (12.122.12.133)  40.248 ms  36.217 ms  37.657 ms
    10  ggr3-ge110.sffca.ip.att.net (12.122.82.169)  33.520 ms  33.155 ms  33.496 ms
    11  so1-3-0-2488M.ar1.SJC2.gblx.net (208.51.134.109)  34.232 ms  47.544 ms  37.849 ms
    12  pos7-0-0.10G.ar2.dca3.gblx.net (67.17.106.181)  82.652 ms  82.326 ms  81.877 ms
    13  146.82.32.82 (146.82.32.82)  82.536 ms  82.609 ms  85.394 ms
    14  * * *
    30  * * *
    ekchain.com
    Code:
    [root@c-67-176-57-155 etc]# traceroute ekchain.com
    traceroute to ekchain.com (72.22.69.90), 30 hops max, 38 byte packets
     1  * * *
     2  68.86.105.169 (68.86.105.169)  9.824 ms  8.616 ms *
     3  * * 10g-9-1-ur02.arvada.co.denver.comcast.net (68.86.103.126)  7.396 ms
     4  * 10g-8-2-ar01.aurora.co.denver.comcast.net (68.86.103.41)  12.073 ms  11.314 ms
     5  68.86.103.170 (68.86.103.170)  8.919 ms  14.681 ms  15.712 ms
     6  12.116.159.5 (12.116.159.5)  9.166 ms  14.584 ms  8.091 ms
     7  tbr1013801.dvmco.ip.att.net (12.123.207.138)  38.274 ms  39.505 ms  37.804 ms
     8  tbr2-cl31.sffca.ip.att.net (12.122.12.133)  43.926 ms  37.957 ms  33.868 ms
     9  ggr3-ge110.sffca.ip.att.net (12.122.82.169)  35.031 ms ggr3-ge90.sffca.ip.att.net (12.122.82.149)  32.993 ms ggr3-ge110.sffca.ip.att.net (12.122.82.169)  32.319 ms
    10  so1-3-0-2488M.ar1.SJC2.gblx.net (208.51.134.109)  35.447 ms  35.882 ms  35.636 ms
    11  so0-3-0-622M.ar1.LAX3.gblx.net (67.17.64.49)  48.822 ms  43.942 ms  43.448 ms
    12  IPowerWeb.ge-0-1-0.ar1.LAX3.gblx.net (67.17.159.170)  43.245 ms  42.624 ms  43.058 ms
    13  * * *
    30  * * *
    cosportbikeclub.org
    Code:
    [root@c-67-176-57-155 etc]# nslookup cosportbikeclub.org
    Server:         68.87.69.146
    Address:        68.87.69.146#53
    
    Non-authoritative answer:
    Name:   cosportbikeclub.org
    Address: 72.54.99.248
    
    [root@c-67-176-57-155 etc]# traceroute cosportbikeclub.org
    traceroute to cosportbikeclub.org (72.54.99.248), 30 hops max, 38 byte packets
     1  * * *
     2  68.86.105.169 (68.86.105.169)  9.250 ms  11.597 ms  9.533 ms
     3  * 10g-9-1-ur02.arvada.co.denver.comcast.net (68.86.103.126)  17.158 ms *
     4  * 10g-8-2-ar01.aurora.co.denver.comcast.net (68.86.103.41)  13.035 ms *
     5  68.86.103.182 (68.86.103.182)  10.128 ms  10.484 ms  9.880 ms
     6  12.116.159.5 (12.116.159.5)  9.770 ms  9.662 ms  9.943 ms
     7  tbr1013801.dvmco.ip.att.net (12.123.207.138)  14.872 ms  9.442 ms  9.726 ms
     8  gar2-p360.dvmco.ip.att.net (12.123.207.161)  14.169 ms  20.887 ms  10.718 ms
     9  12.124.158.146 (12.124.158.146)  26.030 ms  20.042 ms  12.172 ms
    10  * * *
    30  * * *
    Equivalent Windows dumps in the next message.

    Carl

  6. #5
    Just Joined!
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    Dec 2004
    Location
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    And from the Windows side:

    Code:
    E:\Documents and Settings\Carl Schelin>netstat -rn
    
    Route Table
    ===========================================================================
    Interface List
    0x1 ........................... MS TCP Loopback interface
    0x2 ...00 e0 18 b1 dd f2 ...... Intel(R) PRO/100 VE Network Connection - Packet Scheduler Miniport
    ===========================================================================
    ===========================================================================
    Active Routes:
    Network Destination        Netmask          Gateway       Interface  Metric
              0.0.0.0          0.0.0.0     71.229.200.1   71.229.200.92       20
         71.229.200.0    255.255.254.0    71.229.200.92   71.229.200.92       20
        71.229.200.92  255.255.255.255        127.0.0.1       127.0.0.1       20
       71.255.255.255  255.255.255.255    71.229.200.92   71.229.200.92       20
            127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1       1
            224.0.0.0        240.0.0.0    71.229.200.92   71.229.200.92       20
      255.255.255.255  255.255.255.255    71.229.200.92   71.229.200.92       1
    Default Gateway:      71.229.200.1
    ===========================================================================
    Persistent Routes:
      None
    
    E:\Documents and Settings\Carl Schelin>ipconfig /all
    
    Windows IP Configuration
    
            Host Name . . . . . . . . . . . . : blackbeard
            Primary Dns Suffix  . . . . . . . :
            Node Type . . . . . . . . . . . . : Unknown
            IP Routing Enabled. . . . . . . . : No
            WINS Proxy Enabled. . . . . . . . : No
            DNS Suffix Search List. . . . . . : hsd1.co.comcast.net.
    
    Ethernet adapter Local Area Connection:
    
            Connection-specific DNS Suffix  . : hsd1.co.comcast.net.
            Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network Connection
            Physical Address. . . . . . . . . : 00-E0-18-B1-DD-F2
            Dhcp Enabled. . . . . . . . . . . : Yes
            Autoconfiguration Enabled . . . . : Yes
            IP Address. . . . . . . . . . . . : 71.229.200.92
            Subnet Mask . . . . . . . . . . . : 255.255.254.0
            Default Gateway . . . . . . . . . : 71.229.200.1
            DHCP Server . . . . . . . . . . . : 68.87.66.13
            DNS Servers . . . . . . . . . . . : 68.87.69.146
                                                68.87.85.98
            Lease Obtained. . . . . . . . . . : Friday, July 21, 2006 6:34:15 PM
            Lease Expires . . . . . . . . . . : Friday, July 21, 2006 7:34:12 PM
    Amazon.com
    Code:
    E:\Documents and Settings\Carl Schelin>tracert amazon.com
    
    Tracing route to amazon.com [207.171.166.102]
    over a maximum of 30 hops:
    
      1     *        *        *     Request timed out.
      2     *        7 ms     *     68.86.105.169
      3     *        9 ms    16 ms  10g-9-1-ur02.arvada.co.denver.comcast.net [68.86.103.126]
      4     *        *        9 ms  10g-8-2-ar01.aurora.co.denver.comcast.net [68.86.103.41]
      5     9 ms    16 ms    14 ms  68.86.103.182
      6    12 ms    14 ms     9 ms  12.124.157.53
      7    34 ms    33 ms    38 ms  gbr2-a30s2.dvmco.ip.att.net [12.127.4.154]
      8    34 ms    33 ms    35 ms  tbr1-p013601.dvmco.ip.att.net [12.122.1.34]
      9    36 ms    36 ms    43 ms  tbr2-cl31.sffca.ip.att.net [12.122.12.133]
     10    44 ms    36 ms    38 ms  ggr3-ge110.sffca.ip.att.net [12.122.82.169]
     11    35 ms    35 ms    35 ms  so1-3-0-2488M.ar1.SJC2.gblx.net [208.51.134.109]
     12    81 ms    83 ms    81 ms  pos7-0-0.10G.ar2.dca3.gblx.net [67.17.106.181]
     13  146.82.32.82  reports: Destination net unreachable.
    
    Trace complete.
    Alternate address:
    Code:
    E:\Documents and Settings\Carl Schelin>tracert 72.21.206.5
    
    Tracing route to 206-5.amazon.com [72.21.206.5]
    over a maximum of 30 hops:
    
      1     *        *        *     Request timed out.
      2     9 ms    12 ms     *     68.86.105.169
      3     *       10 ms     9 ms  10g-9-1-ur02.arvada.co.denver.comcast.net [68.86.103.126]
      4     8 ms     *        9 ms  10g-8-2-ar01.aurora.co.denver.comcast.net [68.86.103.41]
      5    22 ms     9 ms     9 ms  68.86.103.182
      6    12 ms    13 ms    10 ms  12.116.159.5
      7    36 ms    36 ms    36 ms  tbr1013801.dvmco.ip.att.net [12.123.207.138]
      8    49 ms    43 ms    45 ms  tbr2-cl31.sffca.ip.att.net [12.122.12.133]
      9    38 ms    37 ms    33 ms  ggr3-ge110.sffca.ip.att.net [12.122.82.169]
     10    35 ms    40 ms    35 ms  so1-3-0-2488M.ar1.SJC2.gblx.net [208.51.134.109]
     11    80 ms    81 ms    83 ms  pos7-0-0.10G.ar2.dca3.gblx.net [67.17.106.181]
     12     *        *        *     Request timed out.
     13     *        *        *     Request timed out.
     14     *        *        *     Request timed out.
     15     *        *     146.82.32.82  reports: Destination net unreachable.
    
    Trace complete.
    Which is interesting because I can certainly get to Amazon.com.

    ekchains.com
    Code:
    E:\Documents and Settings\Carl Schelin>tracert ekchain.com
    
    Tracing route to ekchain.com [72.22.69.90]
    over a maximum of 30 hops:
    
      1     *        *        *     Request timed out.
      2    11 ms     *        9 ms  68.86.105.169
      3     *        8 ms     *     10g-9-1-ur02.arvada.co.denver.comcast.net [68.86.103.126]
      4     *        9 ms    12 ms  10g-8-2-ar01.aurora.co.denver.comcast.net [68.86.103.41]
      5    23 ms     9 ms     9 ms  68.86.103.182
      6    12 ms     9 ms     9 ms  12.116.159.5
      7    40 ms    37 ms    37 ms  tbr1013801.dvmco.ip.att.net [12.123.207.138]
      8    35 ms    39 ms    34 ms  tbr2-cl31.sffca.ip.att.net [12.122.12.133]
      9    35 ms    37 ms    33 ms  ggr3-ge90.sffca.ip.att.net [12.122.82.149]
     10    37 ms    43 ms    35 ms  so1-3-0-2488M.ar1.SJC2.gblx.net [208.51.134.109]
     11    46 ms    43 ms    45 ms  so0-3-0-622M.ar1.LAX3.gblx.net [67.17.64.49]
     12    46 ms    52 ms    45 ms  IPowerWeb.ge-0-1-0.ar1.LAX3.gblx.net [67.17.159.170]
     13    43 ms    43 ms    42 ms  host405.ipowerweb.com [72.22.69.90]
    
    Trace complete.
    cosportbikeclub.org
    Code:
    E:\Documents and Settings\Carl Schelin>tracert cosportbikeclub.org
    
    Tracing route to cosportbikeclub.org [72.54.99.248]
    over a maximum of 30 hops:
    
      1     *        *        *     Request timed out.
      2    18 ms    22 ms    11 ms  68.86.105.169
      3     9 ms     *        8 ms  10g-9-1-ur02.arvada.co.denver.comcast.net [68.86.103.126]
      4    14 ms    17 ms     *     10g-8-2-ar01.aurora.co.denver.comcast.net [68.86.103.41]
      5     9 ms     8 ms     8 ms  68.86.103.182
      6    13 ms    11 ms     9 ms  12.116.159.5
      7    12 ms    15 ms     9 ms  tbr2013801.dvmco.ip.att.net [12.123.207.142]
      8    11 ms    12 ms    12 ms  gar2-p370.dvmco.ip.att.net [12.123.207.165]
      9    15 ms    11 ms    12 ms  12.124.158.146
     10     *        *        *     Request timed out.
     11     *        *        *     Request timed out.
     12    20 ms    27 ms    15 ms  172.20.153.142
     13     *        *        *     Request timed out.
     14     *        *        *     Request timed out.
     15     *        *        *     Request timed out.
     16     *        *        *     Request timed out.
     17     *        *        *     Request timed out.
     18     *        *        *     Request timed out.
     19     *        *        *     Request timed out.
     20     *        *        *     Request timed out.
     21     *        *        *     Request timed out.
     22     *        *        *     Request timed out.
     23     *        *        *     Request timed out.
     24     *        *        *     Request timed out.
     25     *        *        *     Request timed out.
     26     *        *        *     Request timed out.
     27     *        *        *     Request timed out.
     28     *        *        *     Request timed out.
     29     *        *        *     Request timed out.
     30     *        *        *     Request timed out.
    
    Trace complete.
    Carl

  7. #6
    Just Joined!
    Join Date
    Dec 2004
    Location
    Broomfield, CO
    Posts
    16
    Oh, another site that's local for us, Windows:

    Code:
    E:\Documents and Settings\Carl Schelin>nslookup rtd-denver.com
    Server:  cns.beaverton.or.bverton.comcast.net
    Address:  68.87.69.146
    
    Non-authoritative answer:
    Name:    rtd-denver.com
    Address:  72.1.97.143
    
    
    E:\Documents and Settings\Carl Schelin>tracert rtd-denver.com
    
    Tracing route to rtd-denver.com [72.1.97.143]
    over a maximum of 30 hops:
    
      1     *        *        *     Request timed out.
      2     8 ms     9 ms     *     68.86.105.169
      3     *        *        *     Request timed out.
      4     9 ms     *        9 ms  10g-8-2-ar01.aurora.co.denver.comcast.net [68.86.103.41]
      5    10 ms     9 ms    10 ms  68.86.103.182
      6    10 ms     9 ms    11 ms  12.124.157.53
      7    10 ms    11 ms     9 ms  12.124.157.6
      8    14 ms    12 ms    13 ms  208-42-224-169.static.data393.net [208.42.224.169]
      9    10 ms    14 ms    14 ms  rtr-dc-dist-d.v17.hosting.data393.net [208.42.224.19]
     10    10 ms    11 ms     9 ms  72-1-97-143.static.data393.net [72.1.97.143]
    
    Trace complete.
    And from the linux box:

    Code:
    [root@c-67-176-57-155 root]# traceroute rtd-denver.com
    traceroute to rtd-denver.com (72.1.97.143), 30 hops max, 38 byte packets
     1  * * *
     2  68.86.105.169 (68.86.105.169)  8.989 ms  7.384 ms *
     3  10g-9-1-ur02.arvada.co.denver.comcast.net (68.86.103.126)  8.020 ms  9.955 ms *
     4  10g-8-2-ar01.aurora.co.denver.comcast.net (68.86.103.41)  9.820 ms  7.993 ms *
     5  68.86.103.174 (68.86.103.174)  15.020 ms  9.175 ms  12.005 ms
     6  12.116.159.5 (12.116.159.5)  9.992 ms  10.113 ms  9.525 ms
     7  tbr2013801.dvmco.ip.att.net (12.123.207.142)  12.028 ms  9.781 ms  12.370 ms
     8  gbr1-p80.dvmco.ip.att.net (12.122.1.37)  15.978 ms  11.018 ms  9.543 ms
     9  br1-a3120s3.dvmco.ip.att.net (12.127.4.157)  9.351 ms  8.553 ms  21.622 ms
    10  12.124.157.6 (12.124.157.6)  10.774 ms  9.856 ms  9.485 ms
    11  208-42-224-173.static.data393.net (208.42.224.173)  9.449 ms  10.607 ms  10.944 ms
    12  rtr-dc-dist-c.v24.hosting.data393.net (208.42.224.26)  9.320 ms  14.060 ms  10.713 ms
    13  * * *
    30  * * *
    Granted, just because I can't get an icmp echo back, doesn't mean diddly but I thought I'd post them as well.

    Thanks again for taking a peek.

    Carl

  8. #7
    Linux Enthusiast KenJackson's Avatar
    Join Date
    Jun 2006
    Location
    Maryland, USA
    Posts
    510
    Well, you're right. I don't see any configuration problem. However, some observations.

    You have different default gateways between Windows (71.229.200.1) and Linux (67.176.56.1), in totally different networks. That seems odd, though they are both Comcast.

    Your own router doesn't return an ICMP timeout packet, so you always get asterisks for both Linux and Windows on the first hop. I wonder if it's not doing anything else.

    Although I can easily browse to all those sites from Linux, I had similar results with traceroute. Wikipedia says there is a difference between Linux traceroute (uses UDP datagrams) and Windows tracert (uses ICMP echo). Linux traceroute has a "-I" switch (capital eye) to allow using echo, though I didn't notice any difference.

    This reminds me of a story. After I recently got my web site setup, I noticed the webhost's help database site seemed to go down. But then I noticed I could access it from work via Verizon, but couldn't access it from home via Comcast. So I complained. Eventually they confessed that they were having severe DOS attacks and they had solved it by isolating the evil doers with their firewall. But unfortunately, they put up a wide enough IP fence to box out me and a few other customers too.

    If you were blocked in a similar way, you wouldn't get through at all, but I wonder if some paths are blocked and others aren't somehow. You are in different address ranges with Linux and Windows, so that would have an effect.

    You might try inspecting the statistics before and after accessing a slow site:
    netstat -st
    or
    netstat -st | grep timeout
    or
    netstat -st | grep -i retransmit

    Maybe you could also rename your /var/lib/dhclient-eth2.leases file and restart the network so you get a different IP address. In fact, you could repeat until you get the same gateway as you have with Windows, to see if that makes a difference.

  9. #8
    Just Joined!
    Join Date
    Dec 2004
    Location
    Broomfield, CO
    Posts
    16
    Quote Originally Posted by KenJackson
    Well, you're right. I don't see any configuration problem. However, some observations.

    You have different default gateways between Windows (71.229.200.1) and Linux (67.176.56.1), in totally different networks. That seems odd, though they are both Comcast.
    Yea, that's my point. I'm not sure if it's a "linksys card, go this way, intel go that way" sort of thing. Notice too that most of the networks start with 72. If it wasn't for the first Amazon traceroute, I'd say it was a problem with an IOS access list somewhere (not that it couldn't still be). I just checked IMDB, another site we can't get to.

    Code:
    [root@c-67-176-57-155 dhcp]# nslookup imdb.com
    Server:         68.87.69.146
    Address:        68.87.69.146#53
    
    Non-authoritative answer:
    Name:   imdb.com
    Address: 72.21.206.75
    Name:   imdb.com
    Address: 207.171.166.140
    Again, 72 and 207 networks just like Amazon.com (in fact, it appears that IMDB and Amazon are right next to each other. Both are 72.21.206 and 207.171.166 networks. Could be neighbors or imdb is owned by amazon.)

    Your own router doesn't return an ICMP timeout packet, so you always get asterisks for both Linux and Windows on the first hop. I wonder if it's not doing anything else.
    Actually it's going to be comcast's router in both cases. In both tests, I was running the commands from the next interface up from the cable box.

    Although I can easily browse to all those sites from Linux, I had similar results with traceroute. Wikipedia says there is a difference between Linux traceroute (uses UDP datagrams) and Windows tracert (uses ICMP echo). Linux traceroute has a "-I" switch (capital eye) to allow using echo, though I didn't notice any difference.

    This reminds me of a story. After I recently got my web site setup, I noticed the webhost's help database site seemed to go down. But then I noticed I could access it from work via Verizon, but couldn't access it from home via Comcast. So I complained. Eventually they confessed that they were having severe DOS attacks and they had solved it by isolating the evil doers with their firewall. But unfortunately, they put up a wide enough IP fence to box out me and a few other customers too.

    If you were blocked in a similar way, you wouldn't get through at all, but I wonder if some paths are blocked and others aren't somehow. You are in different address ranges with Linux and Windows, so that would have an effect.
    Yep, that's what I was suspecting which was why I posted the question. It's not that all of a sudden Amazon went away (or IMDB, etc) but that access would get slower and slower. Timed out once in a while, then more often and now I can't get there at all.

    They are different chipsets too which was why I wanted to get a different card. I have a D-Link I picked up last night and will give that a try as well as putting one of the linksys cards into a Windows box and try it just for a full test.

    You might try inspecting the statistics before and after accessing a slow site:
    netstat -st
    or
    netstat -st | grep timeout
    or
    netstat -st | grep -i retransmit

    Maybe you could also rename your /var/lib/dhclient-eth2.leases file and restart the network so you get a different IP address. In fact, you could repeat until you get the same gateway as you have with Windows, to see if that makes a difference.
    Renaming the file, powering down the cable box, turning off eth2, powering up the cable box, turning on eth2, no effect. Same lease info.

    Here's the current lease file. The first entry is the one that's been working until recently. The second one was a different linksys card (pulled from wife's machine). I had no connectivity with this card. The third one is the third linksys card (pulled from the old router, now an OpenBSD box). There are three entries for the third card right now. By the way, the directory on mandrake at least is /var/lib/dhcp/dhclient-eth2.leases

    Code:
    [root@c-67-176-57-155 dhcp]# cat dhclient-eth2.leases
    lease {
      interface "eth2";
      fixed-address 67.190.17.230;
      option subnet-mask 255.255.254.0;
      option time-offset -21600;
      option routers 67.190.16.1;
      option dhcp-lease-time 223519;
      option dhcp-message-type 5;
      option domain-name-servers 68.87.69.146,68.87.85.98;
      option dhcp-server-identifier 68.87.66.13;
      option broadcast-address 255.255.255.255;
      option domain-name "hsd1.co.comcast.net.";
      renew 4 2006/7/20 00:54:01;
      rebind 5 2006/7/21 05:43:03;
      expire 5 2006/7/21 13:28:43;
    }
    lease {
      interface "eth2";
      fixed-address 71.196.235.237;
      option subnet-mask 255.255.254.0;
      option time-offset -21600;
      option dhcp-lease-time 345600;
      option routers 71.196.234.1;
      option dhcp-message-type 5;
      option dhcp-server-identifier 68.87.66.13;
      option domain-name-servers 68.87.69.146,68.87.85.98;
      option broadcast-address 255.255.255.255;
      option domain-name "hsd1.co.comcast.net.";
      renew 4 2006/7/20 17:52:39;
      rebind 6 2006/7/22 12:12:57;
      expire 0 2006/7/23 00:12:57;
    }
    lease {
      interface "eth2";
      fixed-address 67.176.57.155;
      option subnet-mask 255.255.248.0;
      option time-offset -21600;
      option routers 67.176.56.1;
      option dhcp-lease-time 3600;
      option dhcp-message-type 5;
      option domain-name-servers 68.87.69.146,68.87.85.98;
      option dhcp-server-identifier 68.87.66.13;
      option broadcast-address 255.255.255.255;
      option domain-name "hsd1.co.comcast.net.";
      renew 3 2006/7/19 01:55:12;
      rebind 3 2006/7/19 02:23:45;
      expire 3 2006/7/19 02:31:15;
    }
    Thanks for the further info.

    Carl

  10. #9
    Just Joined!
    Join Date
    Dec 2004
    Location
    Broomfield, CO
    Posts
    16
    Ok, this is getting odd. I put the original linksys card in my wife's Windows 98 system. After getting it plugged back in to the network and bringing it up, I get this:

    Code:
    C:\WINDOWS\Desktop>ipconfig /all
    
    Windows 98 IP Configuration
    
            Host Name . . . . . . . . . : RITA.hsd1.co.comcast.net.
            DNS Servers . . . . . . . . : 68.87.69.146
                                          68.87.85.98
            Node Type . . . . . . . . . : Hybrid
            NetBIOS Scope ID. . . . . . :
            IP Routing Enabled. . . . . : No
            WINS Proxy Enabled. . . . . : No
            NetBIOS Resolution Uses DNS : No
    
    0 Ethernet adapter :
    
            Description . . . . . . . . : PPP Adapter.
            Physical Address. . . . . . : 44-45-53-54-00-00
            DHCP Enabled. . . . . . . . : Yes
            IP Address. . . . . . . . . : 0.0.0.0
            Subnet Mask . . . . . . . . : 0.0.0.0
            Default Gateway . . . . . . :
            DHCP Server . . . . . . . . : 255.255.255.255
            Primary WINS Server . . . . :
            Secondary WINS Server . . . :
            Lease Obtained. . . . . . . :
            Lease Expires . . . . . . . :
    
    1 Ethernet adapter :
    
            Description . . . . . . . . : Linksys LNE100TX(v5) Fast Ethernet Adapter
     NDIS5 Driver
            Physical Address. . . . . . : 00-04-5A-75-92-AF
            DHCP Enabled. . . . . . . . : Yes
            IP Address. . . . . . . . . : 67.190.17.230
            Subnet Mask . . . . . . . . : 255.255.254.0
            Default Gateway . . . . . . : 67.190.16.1
            DHCP Server . . . . . . . . : 68.87.66.13
            Primary WINS Server . . . . : 192.168.2.1
            Secondary WINS Server . . . :
            Lease Obtained. . . . . . . : 07 20 06 11:04:12 PM
            Lease Expires . . . . . . . : 07 23 06 6:24:30 PM
    I can get to amazon.com, ekchain.com, cosportbikeclub.org, imdb.com and rtd-denver.com

    It must be a problem with my linux box but darned if I can figure out what. Back to puzzling things out. I'll post if I figure it out. Feel free to post suggestions though.

    Thanks again.

    Carl

  11. #10
    Just Joined!
    Join Date
    Dec 2004
    Location
    Broomfield, CO
    Posts
    16

    Fixed!

    Hi. I wanted to pass along the fix. I know the comcast folks are also watching this thread.

    I originally thought it was a firewall problem so I eliminated several entries in my iptables (I'm using shorewall to manage it) so I was down to my normal status and it still wasn't working.

    I was doing some reading about routing (unrelated subject) when I had a thought. I was finding more and more 72 Class A networks were unavailable so I thought I'd check things out some more. I checked the shorewall status and examined the settings. I found the following in the /etc/shorewall/rfc1918 file:

    Code:
    0.0.0.0/7               logdrop         # Reserved
    2.0.0.0/8               logdrop         # Reserved
    5.0.0.0/8               logdrop         # Reserved
    7.0.0.0/8               logdrop         # Reserved
    10.0.0.0/8              logdrop         # Reserved
    23.0.0.0/8              logdrop         # Reserved
    27.0.0.0/8              logdrop         # Reserved
    31.0.0.0/8              logdrop         # Reserved
    36.0.0.0/7              logdrop         # Reserved
    39.0.0.0/8              logdrop         # Reserved
    41.0.0.0/8              logdrop         # Reserved
    42.0.0.0/8              logdrop         # Reserved
    58.0.0.0/7              logdrop         # Reserved
    60.0.0.0/8              logdrop         # Reserved
    70.0.0.0/7              logdrop         # Reserved
    72.0.0.0/5              logdrop         # Reserved
    83.0.0.0/8              logdrop         # Reserved
    84.0.0.0/6              logdrop         # Reserved
    88.0.0.0/5              logdrop         # Reserved
    96.0.0.0/3              logdrop         # Reserved
    127.0.0.0/8             logdrop         # Loopback
    197.0.0.0/8             logdrop         # Reserved
    222.0.0.0/7             logdrop         # Reserved
    240.0.0.0/4             logdrop         # Reserved
    I monitored /var/log/messages while I tried to access a 72 Class A network site and saw the site was being dropped and logged. Looks like the 72 network is reserved. So I did some googling and found this:

    Code:
    072/8   Aug 04   ARIN                                (whois.arin.net)
    over Here.

    I picked up the python script referenced in the rfc1918 file and ran the new address file through it. I copied the old rfc1918 file, replaced the reserved space with the new output and restarted the firewall.

    Success. I have access to all the 72 networks and a few others I didn't know I didn't have access to.

    Old rfc1918 reserved entries:

    Code:
    0.0.0.0/7               logdrop         # Reserved
    2.0.0.0/8               logdrop         # Reserved
    5.0.0.0/8               logdrop         # Reserved
    7.0.0.0/8               logdrop         # Reserved
    10.0.0.0/8              logdrop         # Reserved
    23.0.0.0/8              logdrop         # Reserved
    27.0.0.0/8              logdrop         # Reserved
    31.0.0.0/8              logdrop         # Reserved
    36.0.0.0/7              logdrop         # Reserved
    39.0.0.0/8              logdrop         # Reserved
    41.0.0.0/8              logdrop         # Reserved
    42.0.0.0/8              logdrop         # Reserved
    58.0.0.0/7              logdrop         # Reserved
    60.0.0.0/8              logdrop         # Reserved
    70.0.0.0/7              logdrop         # Reserved
    72.0.0.0/5              logdrop         # Reserved
    83.0.0.0/8              logdrop         # Reserved
    84.0.0.0/6              logdrop         # Reserved
    88.0.0.0/5              logdrop         # Reserved
    96.0.0.0/3              logdrop         # Reserved
    127.0.0.0/8             logdrop         # Loopback
    197.0.0.0/8             logdrop         # Reserved
    222.0.0.0/7             logdrop         # Reserved
    240.0.0.0/4             logdrop         # Reserved
    New entries:

    Code:
    0.0.0.0/7               logdrop         # Reserved
    2.0.0.0/8               logdrop         # Reserved
    5.0.0.0/8               logdrop         # Reserved
    7.0.0.0/8               logdrop         # Reserved
    10.0.0.0/8              logdrop         # Reserved
    23.0.0.0/8              logdrop         # Reserved
    27.0.0.0/8              logdrop         # Reserved
    31.0.0.0/8              logdrop         # Reserved
    36.0.0.0/7              logdrop         # Reserved
    39.0.0.0/8              logdrop         # Reserved
    42.0.0.0/8              logdrop         # Reserved
    77.0.0.0/8              logdrop         # Reserved
    78.0.0.0/7              logdrop         # Reserved
    92.0.0.0/6              logdrop         # Reserved
    96.0.0.0/4              logdrop         # Reserved
    112.0.0.0/5             logdrop         # Reserved
    120.0.0.0/8             logdrop         # Reserved
    127.0.0.0/8             logdrop         # Reserved
    173.0.0.0/8             logdrop         # Reserved
    174.0.0.0/7             logdrop         # Reserved
    176.0.0.0/5             logdrop         # Reserved
    184.0.0.0/6             logdrop         # Reserved
    197.0.0.0/8             logdrop         # Reserved
    223.0.0.0/8             logdrop         # Reserved
    240.0.0.0/4             logdrop         # Reserved
    Thanks for taking a look. It's always something simple

    Carl

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