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Hi all. I'm new to this forum. I have a Linux network configuration question. I am testing with Suse Linux Enterprise Server 10 in a VMWare environment. I've installed two ...
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  1. #1
    Just Joined!
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    Dec 2010
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    Getting two Linux servers to communicate (PING issues)


    Hi all. I'm new to this forum. I have a Linux network configuration question.

    I am testing with Suse Linux Enterprise Server 10 in a VMWare environment. I've installed two SLES10 servers, named sles1 and sles2. I can't get the two servers to communicate, even a simple ping won't work.

    The "Network Adapter" in VMWare is set to "bridged", a setting which has worked fine when installing WinXP in VMWare and connecting to the Internet.

    I have configured the Network Settings as follows:

    SLES1:
    -Statically assigned IP Address
    -IP-address: 192.168.0.20
    -Subnet: 255.255.255.0 (/24)
    -Hostname: sles1

    Hostname/DNS tab:
    -Hostname: sles1
    -Domain Name: local
    -Name server: blank

    Routing tab:
    -Default Gateway: 192.168.0.1 (= my router connected to the Internet)

    SLES2: same as sles1, with IP 192.168.0.22 and Hostname sles2

    With these network settings, the two servers seem totally unable to communciate.

    -When I ping sles2 from sles1, I always get the error message:
    connect: Network is unreachable

    -Whatever way I ping, either ping sles2, ping sles2.local, ping 192.168.0.22, whatever, the error message is always the same.

    -Even if I ping sles1 from sles1 (= "pinging myself"), I get the same error message.

    -Only if I ping localhost, I get a proper ping result.

    What did I do wrong? Did I forget to configure something?

    Thank you very much for your help!!
    Kris
    Last edited by orakris; 12-18-2010 at 07:11 PM.

  2. #2
    Just Joined!
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    Can you ping your router?

    Firewalls?

  3. #3
    Linux Engineer Kloschüssel's Avatar
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    Italy
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    How is your VMware host configured? When you are running the virtuals in bridged mode, they will show up on the VMWare host as devices or at least as multiple ip's on a single device. So you'll need to tell us how you set up your bridges. In case they don't show up you need to manually set up static routes to your virtuals on the router and on the vmware host. Otherwise packets won't be routed properly. Physically the structure is most closely described as:


    Code:
    router <--> vmware host <--> vmware virtual1
                            <--> vmware virtual2
    When the vmware virtuals communicate with each other packets should be routed like this:

    Code:
    virtual1 <--> vmware host <--> router <--> vmware host <--> virtual2
    Obviously this kind of setup is hardly discouraged as the maintainance effort is quite high. I would use this setup only if there are at least as much physical network cards as you have virtuals plus one for the vmware host.

    So, we usually have virtuals only to split functionalities physically. I.e. one virtual is the database, the other is the appserver and so on. Then we only have to configure the vmware host to route packets between the virtuals and only specific ports are published to the outside world using NAT where the vmware host behaves like a firewall router to the virtuals.
    Last edited by Kloschüssel; 12-20-2010 at 08:05 AM.

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