# Help to understand "Transparently proxify virtual machines" (docs tutorial)

**URL:** https://discourse.mitmproxy.org/t/help-to-understand-transparently-proxify-virtual-machines-docs-tutorial/483
**Category:** help
**Created:** [May 18, 2017, 5:52pm UTC](https://discourse.mitmproxy.org/t/help-to-understand-transparently-proxify-virtual-machines-docs-tutorial/483 "2017-05-18T17:52:43Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Karu](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/karu/32/234_2.png) [@Karu](https://discourse.mitmproxy.org/u/Karu)
#### Post date: [May 18, 2017, 5:52pm UTC](https://discourse.mitmproxy.org/t/help-to-understand-transparently-proxify-virtual-machines-docs-tutorial/483/1 "2017-05-18T17:52:43Z")

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I have tired to follow the “[Transparently proxify virtual machines](http://docs.mitmproxy.org/en/stable/tutorials/transparent-dhcp.html)” but it is quite confusing.

1. Is ip address “192.168.3.1” random or where can I find it, what should I keep in mind?
2. How can I check that Proxy server is OK before starting to setup clients?
3. In the tutorial is a sentence “install the mitmproxy certificates on the proxied machine”. How should I configure the client machine if it is ubuntu server? What virtual box setting to use?
4. How to debug when the connection in client(proxied machine) is not getting connection to server?
5. I assume the tutorial is about two different virtual machines.

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### Author: ![mhils](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/mhils/32/7_2.png) [@mhils](https://discourse.mitmproxy.org/u/mhils)
#### Post date: [May 21, 2017, 2:08pm UTC](https://discourse.mitmproxy.org/t/help-to-understand-transparently-proxify-virtual-machines-docs-tutorial/483/2 "2017-05-21T14:08:31Z")

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> [@Karu](#):
>
> Is ip address “192.168.3.1” random or where can I find it, what should I keep in mind?

We assign 192.168.3.1 as the IP address of the proxy machine in the internal network. You could use any other (local) IP address, you should need to make sure that you assign DHCP addresses in the same subnet in `/etc/dnsmasq.conf`.

> [@Karu](#):
>
> How can I check that Proxy server is OK before starting to setup clients?

When you invoke mitmproxy it should show up, other than that you need to add a client to view traffic.

> [@Karu](#):
>
> In the tutorial is a sentence “install the mitmproxy certificates on the proxied machine”. How should I configure the client machine if it is ubuntu server? What virtual box setting to use?

This is unrelated of the virtualization technique you are using, see [http://docs.mitmproxy.org/en/stable/certinstall.html](http://docs.mitmproxy.org/en/stable/certinstall.html).

> [@Karu](#):
>
> How to debug when the connection in client(proxied machine) is not getting connection to server?

Check if the proxied machine got an IP address verify in WireShark that it sends packets to the proxy machine.

> [@Karu](#):
>
> I assume the tutorial is about two different virtual machines.

Yes, proxy and proxied machine are differnt. You can have as many proxied machines in the internal network as you want.

Hope this helps!

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### Author: ![Karu](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/karu/32/234_2.png) [@Karu](https://discourse.mitmproxy.org/u/Karu)
#### Post date: [May 21, 2017, 5:57pm UTC](https://discourse.mitmproxy.org/t/help-to-understand-transparently-proxify-virtual-machines-docs-tutorial/483/3 "2017-05-21T17:57:22Z")

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Thanks for your answer. I already managed to get it working (in Transparent mode and not with dnsmasq, but DNS, DDNS and DHCP. Connection between two Ubuntu LTS servers where one is proxy and other proxied).

Trying to find solution, about how to make mitmproxy work in Virtualbox. I was surprised about the lack of tutorials about virtual cluster creation.

I now understand that making mitmproxy run needs quite a lot knowledge about OS, OS debug and specially in computer network. Most confusing is virtual machine vs actual machine - how network configuration differs.
