MikroTik

I've created a PPTP vpn server for about 100 customers.

All the customers are running windows (no mikrotik devices), and are using the pptp connection so that i can remote to their machines (servers in general).

i've created an ppp profile with an local address and no dns setting, but when the client connects it seems that routeros sends out an dns server setting with it's own ip. that makes the server unable to resolve anything -- i dont run, and dont plan to run, and dns server on mikrotik.

how can i prevent routeros sending the dns server setting for pptp connections?

anyone?

handing out dns settings to vpn clients it's a serious change, thoose vpn clients won't be able to use their local dns server and won't be able to resolve their local network names.

To get no DNS server from PPTP, there should be
- no dns configuration at ppp profile;
- allow-remote-requests=no for /ip dns
- server should be empty at /ip dns
Then DNS configuration will not be assigned to client.

ok, i can confirm that it works.

but i have one issue: i need the dns active foro other purposes, not for ppp.

it keep the customer-to-ip mapping.

Look at the client configuration, at least at Windows you can unset "Obtain DNS server address automatically" and use static DNS configuration.
When there is no access to the client device, use the settings from the previous post.

this is a little bit unfortunate.

the vpn i use is kinda public: out customers connect to it so that we can remote to their computers for support.

i cannot afford to change all current and future client connection profiles to use their dns (most of our customers don't even have it dept, some have very powerfull it dept).


it's strange that routeros will hand out dns setting even if there is no dns server on the ppp profile. doens't seem right.

Your PPTP client is asking for DNS settings. RouterOS replies with available DNS settings.
Set DNS cache on other router and forward 53 port traffic from PPTP server, that will allow you to have blank configuration on PPTP server and working DNS cache on the network.

I know this is an old topic but ...

Has this problem been fixed yet?

Having the router assign DNS when no DNS is defined in the PPP profile goes against all sense and must be a bug. Most PPP clients, including ROS, do not have the ability to refuse a DNS allocation without defining a replacement. Surely the PPTP server should not allocate one if the profile DNS Server entry is nulled.

Also, emptying the /ip dns does not solve the problem, until the router is rebooted!!

Mikrotik support giving workarounds to solve this problem indicates an unintended feature (bug) to me.

This bug caused me no end of heartache when I needed to activate /ip dns only for an internal router lookup requirement, and all of a sudden PPP client connected equipment all over the place started to loose local dns capabilities because the PPP client allocated DNS started overiding the locally defined DNS settings.

Any sign of a real solution?

I sort out this problem by setting dns-server=8.8.8.8 in my ppp profile.

I know this is an old topic but ...

Has this problem been fixed yet?

Having the router assign DNS when no DNS is defined in the PPP profile goes against all sense and must be a bug. Most PPP clients, including ROS, do not have the ability to refuse a DNS allocation without defining a replacement. Surely the PPTP server should not allocate one if the profile DNS Server entry is nulled.

Also, emptying the /ip dns does not solve the problem, until the router is rebooted!!

Mikrotik support giving workarounds to solve this problem indicates an unintended feature (bug) to me.

This bug caused me no end of heartache when I needed to activate /ip dns only for an internal router lookup requirement, and all of a sudden PPP client connected equipment all over the place started to loose local dns capabilities because the PPP client allocated DNS started overiding the locally defined DNS settings.

Any sign of a real solution?

No? this problem hasn't fixed.
I sort out with it setting dns-server=8.8.8.8 in my ppp profile.

I sort out with it setting dns-server=8.8.8.8 in my ppp profile.

Its not a solution or a workaround. I want no DNS, so setting the Google DNS doesnt help at all.

well I want to use DNS over the PPTP and I did put a dns server in the profile on the PPP profile. But it doesn't seem like the PPTP client (another mikrotik) will use the DNS...

Any ideas?


/EDIT

actually I just neeed to add the DNS in the DHCP options so my clients got the DNS server. Hope this helps someone.

It seems the bug is still active. It is really wrong to change DNS server list on a client without a direct command, and even without a possibility to prohibit this behavior. If a client runs AD-joined Windows and we change their DNS to ours, their AD fails.

If we want to provide a DNS in PPP - we have a corresponding setting. It is not set by default, and "not set" must mean "we don't give a DNS to a client".

Here is a possible solution.

I noticed setting "255.255.255.255" value to "DNS Server" field of PPP profile prevents DNS assign in Windows XP and Windows 10.

Here is a possible solution.

I noticed setting "255.255.255.255" value to "DNS Server" field of PPP profile prevents DNS assign in Windows XP and Windows 10.

Interesting. I will give that a try. THANKS!!

This bug just bit me in 2018, RotuerOS does NOT behave the way I would expect.

Would be nice if no PPP profie DNS meant no DNS to clients, perhaps an "auto" option for the current behaviour. (Or, add explicit "no dns" option, keeping current behaviour default).