Vagrant: Is there anything in vagrant that changes nameserver in /etc/resolv.conf?

[x-yuri]

I took a look inside centos/7's image and it has

# Generated by NetworkManager
nameserver 192.168.122.1

there. But after I do vagrant up it has

# Generated by NetworkManager
search Dlink
nameserver 10.0.2.3

Do you know what changes that? Is there a way to avoid it? This thing basically introduces this bug.

[x-yuri]

Well, it must be when the network starts that this file is generated. For CentOS this means service network start, for Debian, service networking restart. But I wonder, why for vagrant VMs, it uses virtualbox's DNS server IP address, but when I install the OS manually, it uses my router's IP address...

UPD Changing /etc/resolv.conf and restarting the network brings back virtualbox's DNS server for vagrant VMs, and my router, for non-vagrant ones. Has it to do with some VM settings? Does vagrant set any settings that has to do with this?

$ diff -u <(VBoxManage showvminfo d7) <(VBoxManage showvminfo vagrant-vm_default_1445671341010_37621)
--- /dev/fd/63  2015-10-24 10:39:35.407970094 +0300
+++ /dev/fd/62  2015-10-24 10:39:35.407970094 +0300
@@ -1,11 +1,11 @@
-Name:            d7
+Name:            vagrant-vm_default_1445671341010_37621
 Groups:          /
-Guest OS:        Debian (64-bit)
-UUID:            d4a7d364-a2be-4046-8b1a-8fff6b4e6dea
-Config file:     /home/yuri/VirtualBox VMs/d7/d7.vbox
-Snapshot folder: /home/yuri/VirtualBox VMs/d7/Snapshots
-Log folder:      /home/yuri/VirtualBox VMs/d7/Logs
-Hardware UUID:   d4a7d364-a2be-4046-8b1a-8fff6b4e6dea
+Guest OS:        Ubuntu (64-bit)
+UUID:            faf2f473-44b3-49f3-b84c-d5a66dd28b76
+Config file:     /home/yuri/VirtualBox VMs/vagrant-vm_default_1445671341010_37621/vagrant-vm_default_1445671341010_37621.vbox
+Snapshot folder: /home/yuri/VirtualBox VMs/vagrant-vm_default_1445671341010_37621/Snapshots
+Log folder:      /home/yuri/VirtualBox VMs/vagrant-vm_default_1445671341010_37621/Logs
+Hardware UUID:   faf2f473-44b3-49f3-b84c-d5a66dd28b76
 Memory size:     512MB
 Page Fusion:     off
 VRAM size:       12MB
@@ -19,9 +19,9 @@
 CPUID Portability Level: 0
 CPUID overrides: None
 Boot menu mode:  message and menu
-Boot Device (1): Floppy
-Boot Device (2): DVD
-Boot Device (3): HardDisk
+Boot Device (1): HardDisk
+Boot Device (2): Not Assigned
+Boot Device (3): Not Assigned
 Boot Device (4): Not Assigned
 ACPI:            on
 IOAPIC:          on
@@ -33,7 +33,7 @@
 VT-x VPID:       on
 VT-x unr. exec.: on
 Paravirt. Provider: Legacy
-State:           running (since 2015-10-24T07:33:17.056000000)
+State:           running (since 2015-10-24T07:22:24.797000000)
 Monitor count:   1
 3D Acceleration: off
 2D Video Acceleration: off
@@ -47,24 +47,16 @@
 Autostart Enabled: off
 Autostart Delay: 0
 Default Frontend: 
-Storage Controller Name (0):            IDE
-Storage Controller Type (0):            PIIX4
+Storage Controller Name (0):            SATAController
+Storage Controller Type (0):            IntelAhci
 Storage Controller Instance Number (0): 0
-Storage Controller Max Port Count (0):  2
-Storage Controller Port Count (0):      2
+Storage Controller Max Port Count (0):  30
+Storage Controller Port Count (0):      1
 Storage Controller Bootable (0):        on
-Storage Controller Name (1):            SATA
-Storage Controller Type (1):            IntelAhci
-Storage Controller Instance Number (1): 0
-Storage Controller Max Port Count (1):  30
-Storage Controller Port Count (1):      2
-Storage Controller Bootable (1):        on
-IDE (1, 0): Empty
-SATA (0, 0): /home/yuri/VirtualBox VMs/d7/d7.vdi (UUID: de6c6b66-9513-4599-b5be-ddba46a147a4)
-SATA (1, 0): /home/yuri/VirtualBox VMs/d7/Snapshots/{c95325f6-8db2-4340-8df8-20502112d330}.vmdk (UUID: c95325f6-8db2-4340-8df8-20502112d330)
-NIC 1:           MAC: 08002780208D, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0, Promisc Policy: deny, Bandwidth group: none
+SATAController (0, 0): /home/yuri/VirtualBox VMs/vagrant-vm_default_1445671341010_37621/box-disk1.vmdk (UUID: 5929dece-b0d2-4e9d-8c24-75d09fcfe41d)
+NIC 1:           MAC: 08002748A43B, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0, Promisc Policy: deny, Bandwidth group: none
 NIC 1 Settings:  MTU: 0, Socket (send: 64, receive: 64), TCP Window (send:64, receive: 64)
-NIC 1 Rule(0):   name = ssh, protocol = tcp, host ip = , host port = 2001, guest ip = , guest port = 22
+NIC 1 Rule(0):   name = ssh, protocol = tcp, host ip = 127.0.0.1, host port = 2222, guest ip = , guest port = 22
 NIC 2:           disabled
 NIC 3:           disabled
 NIC 4:           disabled
@@ -72,19 +64,19 @@
 NIC 6:           disabled
 NIC 7:           disabled
 NIC 8:           disabled
-Pointing Device: USB Tablet
+Pointing Device: PS/2 Mouse
 Keyboard Device: PS/2 Keyboard
 UART 1:          disabled
 UART 2:          disabled
 LPT 1:           disabled
 LPT 2:           disabled
-Audio:           enabled (Driver: PulseAudio, Controller: AC97, Codec: STAC9700)
-Clipboard Mode:  disabled
+Audio:           disabled
+Clipboard Mode:  Bidirectional
 Drag and drop Mode: disabled
 Session name:    headless
 Video mode:      720x400x0 at 0,0 enabled
 VRDE:            disabled
-USB:             enabled
+USB:             disabled
 EHCI:            disabled
 XHCI:            disabled

@@ -102,14 +94,16 @@

 Bandwidth groups:  <none>

-Shared folders:  <none>
+Shared folders:  
+
+Name: 'vagrant', Host path: '/home/yuri/_/vagrant-vm' (machine mapping), writable

 VRDE Connection:    not active
 Clients so far:     0

 Video capturing:    not active
 Capture screens:    0
-Capture file:       /home/yuri/VirtualBox VMs/d7/d7.webm
+Capture file:       /home/yuri/VirtualBox VMs/vagrant-vm_default_1445671341010_37621/vagrant-vm_default_1445671341010_37621.webm
 Capture dimensions: 1024x768
 Capture rate:       512 kbps
 Capture FPS:        25
@@ -117,11 +111,16 @@
 Guest:

 Configured memory balloon size:      0 MB
-OS type:                             Debian_64
-Additions run level:                 0
+OS type:                             Linux26_64
+Additions run level:                 2
+Additions version:                   4.3.26_Ubuntu r98988
+

 Guest Facilities:

-No active facilities.
+Facility "VirtualBox Base Driver": active/running (last update: 2015/10/24 07:22:37 UTC)
+Facility "VirtualBox System Service": active/running (last update: 2015/10/24 07:22:44 UTC)
+Facility "Seamless Mode": not active (last update: 2015/10/24 07:22:37 UTC)
+Facility "Graphics Mode": not active (last update: 2015/10/24 07:22:37 UTC)

[x-yuri]

Well, to answer my question, yes, vagrant does enable dns proxy.