VirtualBox

Ticket #13918 (closed defect: fixed)

Opened 3 years ago

Last modified 19 months ago

NAT DNS proxy not working after upgrade to 4.3.24

Reported by: mbalmer Owned by:
Priority: major Component: network/NAT
Version: VirtualBox 4.3.24 Keywords: DNS, NAT proxy
Cc: Guest type: all
Host type: Mac OS X

Description

NAT DNS proxy does not work anymore after upgrading to 4.3.24 from the previous version.

The setup is a NatNetwork without DHCP, 192.168.17.0/24 plus a host only network 192.168.16.0/24.

The guest has 192.168.17.2 (in the nat network) and 192.168.16.2 (in the host only network).

The guest can ping the NAT gateway at 192.168.17.1 and also reach outside hosts by specifying an IP. DNS resolver on the guest is set to 192.168.17.1, i.e. to use the DNS proxy on the NAT gateway. But that does not work anymore after the upgrade.

Attachments

demo_vbox.log Download (96.6 KB) - added by mbalmer 3 years ago.
VBox.Log of a virtual machine that shows the issue
dhcp.cap Download (1.9 KB) - added by Glob3r 19 months ago.
tcpdump capture from the VM poing of view when running dhclient

Change History

Changed 3 years ago by mbalmer

VBox.Log of a virtual machine that shows the issue

comment:1 Changed 3 years ago by mbalmer

I verified the issue with the following guest OSes:

  • Ubuntu Linux 14.04 LTS (i386, 32bit)
  • NetBSD 6.1.5 (amd64, 64bit)

Symptoms are:

  • When logging into to the guest using ssh, there is a significant delay, because the guest tries to reverse lookup my IP address (which eventually fails)
  • nslookup fails after a timout:

# nslookup www.virtualbox.org

;; connection timed out; no servers could be reached

output of # cat /etc/resolf.conf:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)

# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

nameserver 192.168.17.1

comment:2 Changed 3 years ago by mbalmer

FWIW, here is a similar issue on Windows, see ticket #13915.

comment:3 follow-up: ↓ 7 Changed 3 years ago by frank

Please could you verify if the OSX build from our test builds page solves the problem? Thank you!

comment:4 Changed 3 years ago by Mapache

Had to install the new 4.3.25 Vbox Additions. (Mac OSX host, Windows 7 Guest) "NAT Network" works fine. Still no DNS in "NAT" mode.

comment:5 Changed 3 years ago by vushakov

Please, can you provide VM log file for the failed run with "NAT"?

comment:6 Changed 3 years ago by Mapache

Sorry - don't have much time.

DHCP offers an IP but Windows reports an IP address conflict. (although it's definitely not - other machines run with different IP addresses)

comment:7 in reply to: ↑ 3 Changed 3 years ago by mbalmer

Replying to frank:

Please could you verify if the OSX build from our test builds page solves the problem? Thank you!

Sorry for the delay, I am somewhat in holiday ;) Will test now and report back.

comment:8 Changed 3 years ago by mbalmer

Good news: With the test build as of today, the DNS proxy works again (with my original configuration of a Linux guest with eth0 in a NatNetwork and eth1 in a host only network).

Thanks! Will now run 3.2.25r98882 until the next release.

comment:9 Changed 3 years ago by frank

  • Status changed from new to closed
  • Resolution set to fixed

Fix is part of VBox 4.3.26.

comment:10 follow-up: ↓ 11 Changed 3 years ago by da4an1qu1

  • Status changed from closed to reopened
  • Resolution fixed deleted

At risk of drawing ire, I feel compelled to reopen this. I was experiencing the original issue. And VBox 4.3.26 resolved that issue, but only partially. I run two VMs simultaneously. Whilst the first running VM receives updated DNS settings via DHCP when moving from network to network, the second is stuck with the same symptom as first reported in this issue. That is, the DNS is not being updated. Please note, the second VMs NAT is set to 10.0.3.0/24, whilst the firsts is 10.0.2.0/24. The second VM also has a Host-only network adapter configured.

comment:11 in reply to: ↑ 10 Changed 3 years ago by vushakov

Replying to da4an1qu1:

the second is stuck with the same symptom as first reported in this issue. That is, the DNS is not being updated.

The "symptom first reported in this issue" was for DNS proxy in NAT Network. You are apparently talking about NAT. Do you use NAT's DNS proxy? What is your host system?

comment:12 Changed 3 years ago by da4an1qu1

OK. Maybe I've misunderstood the synopsis. The problem I had in 4.3.24 was like this example:

Host obtains an DHCP address on 192.168.1.0/24, and DNS is set as 192.168.1.1 by DNS (home router). Guest 1's NAT adapter obtains IP address 10.0.2.15 and DNS is set as 192.168.1.1, which is reachable due to NAT. Guest 2's NAT adapter obtains IP address 10.0.3.15 and DNS is set as 192.168.1.1 again.

move host to new network, 192.168.0.0/24, and DNS 192.168.0.254 say. Now, Guest 1's NAT adapter is disconnect/reconnected and all details stay same regardless, including now no longer valid DNS 192.168.1.1. Same Guest 2. Both guests difficult to use.

Now the situation is that after moving Guest 2 stays stuck on invalid DNS 192.168.1.1.

The situation is fixed for Guest 1 though, it now gets correct DNS as 192.168.0.254 on the reconnection.

If this is not appropriate for the ticket, I apologise. I can raise a separate ticket if necessary.

comment:13 Changed 3 years ago by vushakov

  • Status changed from reopened to closed
  • Resolution set to fixed

Yes this is not the right ticket. There are several related problems 4.3.{22,24,26} in DNS related code. In 4.3.24 all DNS updates were lost. It was fixed in 4.3.26 but re-introduced #13839 - NAT link flaps on host DHCP renewal (which is exacerbated on networks with very short DHCP lease times).

Changed 19 months ago by Glob3r

tcpdump capture from the VM poing of view when running dhclient

comment:14 Changed 19 months ago by vushakov

What is that capture supposed to demonstrate?

Note: See TracTickets for help on using tickets.

www.oracle.com
ContactPrivacy policyTerms of Use