CentOS Networking with V Box

Michael Torres matorres124 at gmail.com
Tue Feb 3 23:45:38 MST 2015 

thats the point.... I dont have an IP address...there is nothing that I put
to scan it.  My NIC was allowing it when I was at Starbucks..  That is why
I think its my router, as such isnt the router that assigns IP address to
the network when using DHCP?

On Tue, Feb 3, 2015 at 11:39 PM, Kevin Fries <kevin at fries-biro.com> wrote:

> Ok, down to two possibilities.
>
> Nmap is a scanner.  It is trying to identify your VM and probe for open
> ports.
>
> When you scanned by name... it did not understand that name.  Your router
> is external to all of this, and should not be involved at all.
>
> Try nmap by IP address.
>
> If that still results in nothing, add a virtual network via VMware or
> VBox.  Next add a new virtual network adapter to your VM, and connect it to
> the new network.  This should be a private network between host and
> client.  Config your interface in the VM.  This will resolve your problem.
> In this case, your NIC is not allowing traffic to go out, then back in to
> itself.  The traffic is almost certainly not going to your router then back.
>
> HTH
> Kevin
> On Feb 3, 2015 10:41 PM, "Michael Torres" <matorres124 at gmail.com> wrote:
>
>> netstat -plant
>>
>> liastening on ports 25 and 22 both for IPv4 nad IPv6
>>
>> Result from the nmap(windows version)
>> Starting Nmap 6.47 ( http://nmap.org ) at 2015-02-03 22:36 US Mountain
>> Standard Time
>>
>> NSE: Loaded 118 scripts for scanning.
>>
>> NSE: Script Pre-scanning.
>>
>> NSE: Script Post-scanning.
>>
>> Read data files from: C:\Program Files (x86)\Nmap
>>
>> Nmap done: 0 IP addresses (0 hosts up) scanned in 4.20 seconds
>>
>>            Raw packets sent: 0 (0B) | Rcvd: 0 (0B)
>>
>> Failed to resolve "devserver".
>>
>> WARNING: No targets were specified, so 0 hosts scanned.
>>
>> I would ahave asusmed the the above results as the dhcp server is not
>> generating a IPv4 address
>>
>>
>> so...
>>
>>   1) The netstat does not show the binding to port 21... this means SSHD
>> did not start.
>>
>> I am guessing port 22 is OK
>>
>>   2) netstat shows SSHD, but the firewall is not allowing it.  Open the
>> firewall
>>
>> Firewall is already disabled
>>
>>   3) netstat shows SSHD, the firewall is open, but you still don't see
>> the port open via nmap.
>>
>>     3a) if you see other ports open, I would look at the Windows firewall
>>
>> Windows firewall allowed it on a Public network (startbuck), so why not
>> allow it at my home
>>
>>     3b) If you don't see any ports open, you have two options here.
>>
>>        3b1) Make sure your NIC (from the Windows side) is in promiscuous
>> mode.
>>
>> dont know how to do that.
>>
>>        3b2) If it is already in promiscuous mode, then this may not work
>> in this configuration.  In this case, try adding a private network on a
>> second NIC, and communicate with the VM over that.
>> Ill try to connect to my ethernet adpater and see if that is it, maybe
>> its my wireless adapter....
>>
>> Mike
>>
>>
>> On Tue, Feb 3, 2015 at 10:22 PM, Kevin Fries <kevin at fries-biro.com>
>> wrote:
>>
>>> Ok, sorry, I misunderstood.
>>>
>>> Nmap could be your friend here.  Install it on your Windows machine.  It
>>> will install the graphical tool automatically in Windows.  Point this at
>>> your VM, and do a "intense scan"
>>>
>>> Next, on the Linux VM, do a
>>>   # netstat -plant
>>>
>>> Zenmap/Nmap will tell you what ports it can see open from its side of
>>> the link.  The netstat command will tell you which ports are opened by
>>> running software.
>>>
>>> Lastly, on the Linux VM, do a
>>>    # ip tables -L
>>>
>>> This will tell you which ports the firewall will allow.
>>>
>>> Now, you have a few possibilities:
>>>
>>>   1) The netstat does not show the binding to port 21... this means SSHD
>>> did not start.
>>>
>>>   2) netstat shows SSHD, but the firewall is not allowing it.  Open the
>>> firewall
>>>
>>>   3) netstat shows SSHD, the firewall is open, but you still don't see
>>> the port open via nmap.
>>>
>>>     3a) if you see other ports open, I would look at the Windows firewall
>>>
>>>     3b) If you don't see any ports open, you have two options here.
>>>
>>>        3b1) Make sure your NIC (from the Windows side) is in promiscuous
>>> mode.
>>>
>>>        3b2) If it is already in promiscuous mode, then this may not work
>>> in this configuration.  In this case, try adding a private network on a
>>> second NIC, and communicate with the VM over that.
>>>
>>> Let me how it goes.
>>>
>>> Kevin
>>> On Feb 3, 2015 9:58 PM, "Michael Torres" <matorres124 at gmail.com> wrote:
>>>
>>>> Well, no,  I didnt issue any commands other than
>>>> /path/to/network/script/network start /path/to/network/script/network stop
>>>> and the commands to disable firewall/SELINUX
>>>>
>>>> I know I didnt use any systemctrl commands., but I tried to run the
>>>> commands that you just provided and nothing happened.  I should probably
>>>> say that I know that IPv6 is enalbed and have network connection to the net
>>>> work and I can ping yahoo.com etc.....  I just cant SSH(putty) to the
>>>> server.
>>>>
>>>> This all leads me to beleive that there is a configuration in my router
>>>> that is not allowing me to get a IPv4 address. Does the default gateway
>>>> have to be a certain number?  I have manually configured that IP on my
>>>> router a long  time ago, but even then I had Bridged networking working
>>>> correctly.
>>>>
>>>> Mike
>>>>
>>>>
>>>>
>>>> On Tue, Feb 3, 2015 at 9:48 PM, Kevin Fries <kevin at fries-biro.com>
>>>> wrote:
>>>>
>>>>> Your network is probably not getting started.  The enp0p3 is the name
>>>>> of an interface started almost definantly  by systemd, not the old RHEL
>>>>> way.  This is likely why the networking-scripts didn't work.
>>>>>
>>>>> When you were at Starbucks, you likely did a systemctl start on the
>>>>> interface.  Look in your history for it.  If you find it, issue the same
>>>>> command again.  If your interface comes up correctly,  reissue the command
>>>>> once again, substituting enable for start.  This second command is similar
>>>>> to a chkconfig command.
>>>>>
>>>>> Let me know how that works.
>>>>>
>>>>> Kevin
>>>>> On Feb 3, 2015 9:13 PM, "Michael Torres" <matorres124 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> The result of that command is:
>>>>>>
>>>>>> 0 loaded units listed
>>>>>>
>>>>>>
>>>>>> So I ran a what it suggested: systemctl list-unit-files
>>>>>> majority of everything says "static"  but some are "enabled" or
>>>>>> "disabled"
>>>>>>
>>>>>> again, because  I cannot copy or capture a screen shot, is there a
>>>>>> specific list item that you need to see?"
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Tue, Feb 3, 2015 at 8:44 PM, Kevin Fries <kevin at fries-biro.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Do a
>>>>>>>
>>>>>>> # systemctl --failed
>>>>>>>
>>>>>>> And post the results
>>>>>>>
>>>>>>> Kevin
>>>>>>> On Feb 3, 2015 8:37 PM, "Michael Torres" <matorres124 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Arrghh....yes its configured.  But I am having an issue getting the
>>>>>>>> cat /etc/sysconfig/network-script/ifcfg-enp0s3..........because I cant
>>>>>>>> connect,  I cant ssh in to use outty so I can copy using my mouse.  I tried
>>>>>>>> taking a screen shot, but VBox for some reason wont display on on the
>>>>>>>> "print screen"command.
>>>>>>>>
>>>>>>>> is there a particular setting you are looking for?  again, the file
>>>>>>>> is configured and it is reading it.
>>>>>>>>
>>>>>>>> Mike
>>>>>>>>
>>>>>>>> On Tue, Feb 3, 2015 at 8:15 PM, Stephen M <smelheim85 at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> I don't remember if this is a problem in centos 7 as it was in 6.
>>>>>>>>> But check to make sure the eth0 is configured.   But yes a print out of
>>>>>>>>> ifconfig inside vox would be great.
>>>>>>>>> On Feb 3, 2015 8:07 PM, "Michael Torres" <matorres124 at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> Hello all,
>>>>>>>>>>
>>>>>>>>>> I have an problem that  I cannot seem to figure out.....
>>>>>>>>>>
>>>>>>>>>> I am trying to use "Bridged" networking in Virtual Box to a
>>>>>>>>>> CentOS 7 minimum install distro that I want to use for my development
>>>>>>>>>> server.
>>>>>>>>>>
>>>>>>>>>> I have used Bridged networking in the past and never had any
>>>>>>>>>> issues but that was with older versions of CentOS
>>>>>>>>>>
>>>>>>>>>> The issue....  DHCP will not assign a IPv4 address to the server.
>>>>>>>>>>
>>>>>>>>>> Here is the weird part...  I was at startbucks and actually got
>>>>>>>>>> it to work! (Please, hold the "Just use it at starbucks then" comments..I
>>>>>>>>>> know....)
>>>>>>>>>>
>>>>>>>>>> Here is the process I used...
>>>>>>>>>>
>>>>>>>>>> -Installed a fresh CentOS 7 on VBox
>>>>>>>>>> -While on NAT,  I performed "yum update" so my server was fresh
>>>>>>>>>> with the latest
>>>>>>>>>> -Disabled SELinux
>>>>>>>>>> -Disabled the Firewall
>>>>>>>>>> -Shut down server to reconfigure the adapter to "Bridged"
>>>>>>>>>> -used adapter type of "Intel Pro 1000 MT Desktop (82540EM)"
>>>>>>>>>> -set it to "Promiscuous Mode"
>>>>>>>>>> -restart the server
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Again, at Starbucks it assigned a IP address, so this leads me to
>>>>>>>>>> believe that the issue is with a configuration on my router.
>>>>>>>>>>
>>>>>>>>>> I am not very good at networking, so any help would be
>>>>>>>>>> appreciated.
>>>>>>>>>>
>>>>>>>>>> If you need error messages or other output, let me know (and
>>>>>>>>>> possibly the command as I don't know networking that well other than
>>>>>>>>>> "ifconfig")
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Mike
>>>>>>>>>>
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