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I am new to Linux and am installing my first copy of Red Hat 5.4 x86 64 bit on a virtual server. The physical box is a Dell PowerEdge 2900 ...
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  1. #1
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    Red Hat Networking Problem


    I am new to Linux and am installing my first copy of Red Hat 5.4 x86 64 bit on a virtual server. The physical box is a Dell PowerEdge 2900 with dual quad core processors and 16 GB ram. The Network card is a 1 Gb Intel EtherExpress/1000 card that I am connecting through to access the vSphere 5 hypervisor. I was able to install the Linux OS and everything looks good. I gave the RH VM 100 GB of disk space. If I look at the configuration on the Vsphere for networking everything looks good. However my VM server will not connect to the internet. The network card says it is configured and active but will not connect. When I try I get nothing, the Firefox says Address not Found for any address entered. I have used both static and dynamic IPs for my system.

    Any Ideas where to look?

  2. #2
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    Hello and welcome!

    Hopefully you can use your VM host's internet connection. I'm not familiar w/VMware so I can't speak to that.

    But as far as the Linux side, you need a couple of things, namely:

    1) a default gateway (i.e., a way to get out onto your router and beyond to the internet)

    2) DNS servers (i.e., a way to resolve an ip address, like 1.2.3.4, to a domain name, like google.com)

    for the default gw, you probably want to use the ip address of your VM host that "faces" your Linux guest. it is probably on the same subnet. find your Linux ip address first by looking at the output of "ifconfig". say you see 192.168.1.2 as the ip for eth0. Now look on your host for the ip address information and look for one on the same subnet, like 192.168.1.50, for example. so that is the ip address that you probably want to use as your default gateway.

    to check the current default gateway, run this command:
    Code:
    route -n
    look for a line with an ip address in the 2nd column, instead of 0.0.0.0 - and that is likely your default gateway. if none is there, and you know the ip address of your host to use, add it like this (as root):
    Code:
    route add default gw 192.168.1.50 dev eth0
    To add your DNS servers, you just need to know an ip address of a DNS server that you can use. You can probably use the same DNS servers that your host is using. Or sometimes the DNS server of a guest is the ip address of the host, it just depends. but say you find that it is "1.2.3.4" on your host system. on your Linux guest, they go in a file called "/etc/resolv.conf" and the file should look like this:

    Code:
    nameserver 1.2.3.4
    nameserver 1.2.3.5
    Note that it can get complicated by NAT and Bridging and other advanced network settings that the VMhost imposes on the guest. But at the least, you do need a default gw and nameservers defined on your Linux box, that much is sure.

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    I checked and everything was all ready set up as you suggested but still no connection to the internet.

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    Then my guess is that it is some peculiarity in the VMware/Vsphere configuration. Perhaps you could find the answer here.

  5. #5
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    Step one in troubleshooting connectivity problems for any device on a network:
    Can you ping your gateway?

    Are you assigning a static IP, or are you using DHCP. If you're using DHCP from a router, try pinging that router. If you get no ping response, then you have no connectivity to the router, thus won't have connectivity to the internet.

    If you can ping your router, then you likely don't have DNS. If you set up your IP manually, you have to enter DNS manually. This, can be your router's (gateway) IP, your ISP's DNS IP, your own network's DNS (if you set up a DNS server yourself) or any public/third party DNS service, such as google's free DNS at 8.8.8.8

    The DNS can be configured with system-config-network command, it will give you an option to set DNS.

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    I should have stated it better. My issue is connecting from my Red Hat Server to anything through my VM server. I cannot ping anything (DNS Server, Gateway, Switches, another Server, or the Internet) through the VM Linus server. (Everything was set up properly by our sys admin. DNS, Gateway, etc.) I know the NIC card is working as I can connect to the physical server through vSphere and hence to the VM Linux server and its GUI and open a terminal window, issue commands etc. I just cannot connect back out of the VM Linux server to our network or the internet. I have a lot of experience with Windows servers but not Linux. I worked with NEXT in the early 90s but have not worked with Linux until I started this job. I am going to use this server and instance of Linux as a test box so I don’t screw up any of our live servers.

  7. #7
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    Quote Originally Posted by bghanson View Post
    I should have stated it better. My issue is connecting from my Red Hat Server to anything through my VM server. I cannot ping anything (DNS Server, Gateway, Switches, another Server, or the Internet) through the VM Linus server. (Everything was set up properly by our sys admin. DNS, Gateway, etc.) I know the NIC card is working as I can connect to the physical server through vSphere and hence to the VM Linux server and its GUI and open a terminal window, issue commands etc. I just cannot connect back out of the VM Linux server to our network or the internet. I have a lot of experience with Windows servers but not Linux. I worked with NEXT in the early 90s but have not worked with Linux until I started this job. I am going to use this server and instance of Linux as a test box so I donít screw up any of our live servers.
    Have you got any other virtual box that is working on the same physical server?

  8. #8
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    Quote Originally Posted by bghanson View Post
    I should have stated it better. My issue is connecting from my Red Hat Server to anything through my VM server. I cannot ping anything (DNS Server, Gateway, Switches, another Server, or the Internet) through the VM Linus server. (Everything was set up properly by our sys admin. DNS, Gateway, etc.) I know the NIC card is working as I can connect to the physical server through vSphere and hence to the VM Linux server and its GUI and open a terminal window, issue commands etc. I just cannot connect back out of the VM Linux server to our network or the internet. I have a lot of experience with Windows servers but not Linux. I worked with NEXT in the early 90s but have not worked with Linux until I started this job. I am going to use this server and instance of Linux as a test box so I donít screw up any of our live servers.
    Have you established connectivity to your default gateway from within your VM guest? i.e., what is it, and have you yourself pinged it from your VM guest? can you ping the DNS servers?

  9. #9
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    The description of your setup is painfully unclear.

    Here's what you should do:
    1) List your setup. Which VMs are on what physical hosts, and what IP everything has.
    2) List your network setup

    After you have typed all that out:
    3) Describe precisely what you're trying to do, such as:
    I'm trying to ping the virtual server named 'web server' with ip xxx on physical host A with ipxxx, from virtual server named 'ping server' with ip xxx on physical host B....etc.

    Also, describe what's going on with your VMware network setup. VMware guests have virtual nics, which connect to virtual networks. Those virtual networks connect to other virtual networks and phyiscal networks.

  10. #10
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    Any VLAN has been setup on the host? Is the Linux VM on same network as the host? Can you attach the settings of VM?

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