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I have 2 servers: xmail1 192.168.1.21 xmail2 192.168.1.22 THE PROBLEM: [root@xmail1 ~]# nslookup 64.81.79.2 ;; connection timed out; no servers could be reached [root@xmail2 ~]# nslookup 64.81.79.2 Server: 64.81.79.2 Address: ...
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  1. #1
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    nslookup: connection timed out; no servers could be reached


    I have 2 servers:

    xmail1 192.168.1.21
    xmail2 192.168.1.22

    THE PROBLEM:

    [root@xmail1 ~]# nslookup 64.81.79.2
    ;; connection timed out; no servers could be reached

    [root@xmail2 ~]# nslookup 64.81.79.2
    Server: 64.81.79.2
    Address: 64.81.79.2#53

    Non-authoritative answer:
    2.79.81.64.in-addr.arpa name = dns.sfo1.speakeasy.net.

    Authoritative answers can be found from:


    Logging in and sendmail are slow as a result. I can ssh and ping to local machines from xmail1, and sendmail successfully sends slowly, but it's really gummed up because of the DNS issue here.

    Here are a few configs I've tried for xmail1 that have failed and xmail2's which works:

    [root@xmail1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
    DEVICE=eth0
    BOOTPROTO=none
    BROADCAST=192.168.1.255
    HWADDR=00:30:48:59:A1:F8
    IPADDR=192.168.1.21
    NETMASK=255.255.255.0
    NETWORK=192.168.1.0
    ONBOOT=yes
    TYPE=Ethernet
    USERCTL=no
    PEERDNS=yes
    GATEWAY=192.168.1.1
    IPV6INIT=no

    [root@xmail1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
    # Broadcom Corporation NetXtreme BCM5704 Gigabit Ethernet
    DEVICE=eth0
    BOOTPROTO=none
    BROADCAST=192.168.1.255
    HWADDR=00:30:48:59:a1:f8
    IPADDR=192.168.1.21
    NETMASK=255.255.255.0
    NETWORK=192.168.1.0
    ONBOOT=yes
    GATEWAY=192.168.1.1
    TYPE=Ethernet

    [root@xmail1 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
    # Broadcom Corporation NetXtreme BCM5704 Gigabit Ethernet
    DEVICE=eth0
    BOOTPROTO=none
    BROADCAST=192.168.1.255
    HWADDR=00:30:48:59:a1:f8
    IPADDR=192.168.1.21
    NETMASK=255.255.255.0
    NETWORK=192.168.1.0
    ONBOOT=yes
    GATEWAY=192.168.1.1
    TYPE=Ethernet
    PEERDNS=no

    [root@xmail2 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
    DEVICE=eth0
    BOOTPROTO=none
    BROADCAST=192.168.1.255
    HWADDR=00:12:3F:ED:08:5A
    IPADDR=192.168.1.22
    NETMASK=255.255.255.0
    NETWORK=192.168.1.0
    ONBOOT=yes
    TYPE=Ethernet
    USERCTL=no
    PEERDNS=yes
    GATEWAY=192.168.1.1
    IPV6INIT=no

    RESOLV.CONF:

    [root@xmail1 ~]# cat /etc/resolv.conf
    search glocap.com
    nameserver 64.81.79.2
    nameserver 216.231.41.2

    [root@xmail2 ~]# cat /etc/resolv.conf
    search glocap.com
    #nameserver 192.168.1.20
    nameserver 64.81.79.2 #speakeasy
    nameserver 216.231.41.2 #speakeasy
    # nameserver 209.17.66.100
    # nameserver 209.17.66.79

    ROUTE:

    [root@xmail1 ~]# route
    Kernel IP routing table
    Destination Gateway Genmask Flags Metric Ref Use Iface
    192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
    link-local * 255.255.0.0 U 0 0 0 eth0
    default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

    [root@xmail2 ~]# route
    Kernel IP routing table
    Destination Gateway Genmask Flags Metric Ref Use Iface
    192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
    169.254.0.0 * 255.255.0.0 U 0 0 0 eth0
    default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

    Note: the last line (gateway) of xmail1's 'route' command loads very slowly, I think it might be related.

    Thanks so much for any response!

    Kimball

  2. #2
    Linux Engineer rcgreen's Avatar
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    What are you using for your gateway?

  3. #3
    Linux Guru Lazydog's Avatar
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    Can both servers ping the ip address?
    Can you traceroute to the ip address?

    What does the following spit out from both machines:

    Code:
    dig +trace -x 64.81.79.2

    Regards
    Robert

    Linux
    The adventure of a life time.

    Linux User #296285
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  4. #4
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    dig output

    [root@xmail2 ~]# ping 64.81.79.2
    PING 64.81.79.2 (64.81.79.2) 56(84) bytes of data.
    64 bytes from 64.81.79.2: icmp_seq=0 ttl=58 time=2.89 ms
    64 bytes from 64.81.79.2: icmp_seq=1 ttl=58 time=2.84 ms
    64 bytes from 64.81.79.2: icmp_seq=2 ttl=58 time=3.11 ms
    64 bytes from 64.81.79.2: icmp_seq=3 ttl=58 time=2.90 ms
    64 bytes from 64.81.79.2: icmp_seq=4 ttl=58 time=2.99 ms

    --- 64.81.79.2 ping statistics ---
    5 packets transmitted, 5 received, 0% packet loss, time 4003ms
    rtt min/avg/max/mdev = 2.841/2.950/3.113/0.100 ms, pipe 2


    [root@xmail2 ~]# traceroute 64.81.79.2
    traceroute to 64.81.79.2 (64.81.79.2), 30 hops max, 38 byte packets
    1 192.168.1.1 (192.168.1.1) 0.221 ms 0.201 ms 0.137 ms
    2 207.7.135.65 (207.7.135.65) 1.227 ms 1.212 ms 2.157 ms
    3 209.237.229.209 (209.237.229.209) 23.379 ms 191.684 ms 0.576 ms
    4 Vlan902.br01-paix-pao.unitedlayer.com (207.7.129.73) 0.976 ms 0.927 ms 0.851 ms
    5 ge4-0.mpr2.pao1.us.mfnx.net (198.32.176.11) 1.855 ms 1.709 ms 1.725 ms
    6 so-0-0-0.mpr3.pao1.us.above.net (64.125.27.81) 1.731 ms 1.842 ms 1.717 ms
    7 t444-abovenet-speakeasy.net (209.249.11.17 2.856 ms 3.085 ms 3.225 ms
    8 dns.sfo1.speakeasy.net (64.81.79.2) 2.850 ms 2.961 ms 3.089 ms

    [root@xmail2 ~]# dig +trace -x 64.81.79.2

    ; <<>> DiG 9.3.1 <<>> +trace -x 64.81.79.2
    ;; global options: printcmd
    ;; connection timed out; no servers could be reached

    [root@xmail1 ~]# ping 74.125.19.104
    PING 74.125.19.104 (74.125.19.104) 56(84) bytes of data.
    <hangs>

    [root@xmail1 ~]# traceroute 64.81.79.2
    traceroute to 64.81.79.2 (64.81.79.2), 30 hops max, 40 byte packets
    1 (192.168.1.1) 0.155 ms 0.132 ms 0.118 ms
    2 * * *
    3 * * *
    4 * * *
    5 * * *
    6 * * *
    7 * * *
    8 * * *
    9 * * *
    10 * * *
    11 * * *
    12 * * *
    13 * * *
    14 * * *
    15 * * *
    16 * * *
    17 * * *
    18 * * *
    19 * * *
    20 * * *
    21 * * *
    22 * * *
    23 * * *
    24 * * *
    25 * * *
    26 * * *
    27 * * *
    28 * * *
    29 * * *
    30 * * *

    [root@xmail1 ~]# dig +trace -x 64.81.79.2

    ; <<>> DiG 9.5.0a6 <<>> +trace -x 64.81.79.2
    ;; global options: printcmd
    ;; connection timed out; no servers could be reached

  5. #5
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    rcgreen,

    I'm using a Linux box with iptables as a firewall/gateway. The config seems to be consistent internally. I actually have 2 boxes with this problem, and at least 7 other boxes in the same subnet are working fine, so I'm fairly confident it's a problem with the individual machines.

    thanks so much for your help!

  6. #6
    Linux Guru Lazydog's Avatar
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    Quote Originally Posted by kbighorse View Post
    [root@xmail2 ~]# ping 64.81.79.2
    PING 64.81.79.2 (64.81.79.2) 56(84) bytes of data.
    64 bytes from 64.81.79.2: icmp_seq=0 ttl=58 time=2.89 ms
    64 bytes from 64.81.79.2: icmp_seq=1 ttl=58 time=2.84 ms
    64 bytes from 64.81.79.2: icmp_seq=2 ttl=58 time=3.11 ms
    64 bytes from 64.81.79.2: icmp_seq=3 ttl=58 time=2.90 ms
    64 bytes from 64.81.79.2: icmp_seq=4 ttl=58 time=2.99 ms

    --- 64.81.79.2 ping statistics ---
    5 packets transmitted, 5 received, 0% packet loss, time 4003ms
    rtt min/avg/max/mdev = 2.841/2.950/3.113/0.100 ms, pipe 2


    [root@xmail2 ~]# traceroute 64.81.79.2
    traceroute to 64.81.79.2 (64.81.79.2), 30 hops max, 38 byte packets
    1 192.168.1.1 (192.168.1.1) 0.221 ms 0.201 ms 0.137 ms
    2 207.7.135.65 (207.7.135.65) 1.227 ms 1.212 ms 2.157 ms
    3 209.237.229.209 (209.237.229.209) 23.379 ms 191.684 ms 0.576 ms
    4 Vlan902.br01-paix-pao.unitedlayer.com (207.7.129.73) 0.976 ms 0.927 ms 0.851 ms
    5 ge4-0.mpr2.pao1.us.mfnx.net (198.32.176.11) 1.855 ms 1.709 ms 1.725 ms
    6 so-0-0-0.mpr3.pao1.us.above.net (64.125.27.81) 1.731 ms 1.842 ms 1.717 ms
    7 t444-abovenet-speakeasy.net (209.249.11.17 2.856 ms 3.085 ms 3.225 ms
    8 dns.sfo1.speakeasy.net (64.81.79.2) 2.850 ms 2.961 ms 3.089 ms

    [root@xmail2 ~]# dig +trace -x 64.81.79.2

    ; <<>> DiG 9.3.1 <<>> +trace -x 64.81.79.2
    ;; global options: printcmd
    ;; connection timed out; no servers could be reached
    OK, looking at the above you are allowing ping to travel through the firewall to the external site. But it seems you are blocking DNS from this server.

    [root@xmail1 ~]# ping 74.125.19.104
    PING 74.125.19.104 (74.125.19.104) 56(84) bytes of data.
    <hangs>

    [root@xmail1 ~]# traceroute 64.81.79.2
    traceroute to 64.81.79.2 (64.81.79.2), 30 hops max, 40 byte packets
    1 (192.168.1.1) 0.155 ms 0.132 ms 0.118 ms
    2 * * *
    3 * * *
    4 * * *
    5 * * *
    6 * * *
    7 * * *
    8 * * *
    9 * * *
    10 * * *
    11 * * *
    12 * * *
    13 * * *
    14 * * *
    15 * * *
    16 * * *
    17 * * *
    18 * * *
    19 * * *
    20 * * *
    21 * * *
    22 * * *
    23 * * *
    24 * * *
    25 * * *
    26 * * *
    27 * * *
    28 * * *
    29 * * *
    30 * * *

    [root@xmail1 ~]# dig +trace -x 64.81.79.2

    ; <<>> DiG 9.5.0a6 <<>> +trace -x 64.81.79.2
    ;; global options: printcmd
    ;; connection timed out; no servers could be reached
    Looking at this setup you are not allowing ping or DNS traffic to pass (I am assuming 192.168.1.1 is your firewall). Since you stated that you have 7 other machines that do not have a problem I would suggest you look hard at the firewall and ensure that you are not blocking traffic from these machines.

    If you like you could post your rules for us to look and see where the problem might be.

    Regards
    Robert

    Linux
    The adventure of a life time.

    Linux User #296285
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