CentOS Networking with V Box
Kevin Fries
kevin at fries-biro.com
Tue Feb 3 23:39:09 MST 2015
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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