DNS issue while connected to OpenVPN
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Hi All,
Im having DNS issue on random users while connected to OpenVPN.
OpenVPN is connected successfully with out any issue, BUT the moment users tries to RDP into their office computer they can't connect hostname is unable to resolve.
Looks like there is DNS leak. We have encountered this issue on both Win7 and Win10.
Appreciate any advice.
Thanks,
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When you exported the configuration for Windows clients, did you check the Block Outside DNS option?
Though the option that enables should only be relevant on Windows 10.
It adds this to the OpenVPN configuration:
setenv opt block-outside-dnsAlso make sure that the DNS resolver is configured with an ACL to allow the OpenVPN client subnet to make DNS queries.
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Hi Jimp,
When you exported the configuration for Windows clients, did you check the Block Outside DNS option? Nope i didn't tick this option when i export the Windows client configuration.
will this work if tick only on the OpenVPN server? or the Windows client export must also have?
Also make sure that the DNS resolver is configured with an ACL to allow the OpenVPN client subnet to make DNS queries. where can i check this?
Thanks,
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@albertmiclat said in DNS issue while connected to OpenVPN:
will this work if tick only on the OpenVPN server? or the Windows client export must also have?
That is not a server-side option. It only works on Windows clients so it would go in the Windows client configuration.
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@jimp
That is not a server-side option. It only works on Windows clients so it would go in the Windows client configuration. i noticed on the server configuration this option is also visible.
Also make sure that the DNS resolver is configured with an ACL to allow the OpenVPN client subnet to make DNS queries. where can i check this?
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Yes, but it pushes that to the client, it doesn't affect how the server behaves.
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@jimp
Ok, so if i want this setting to be active i must export a new Windows client configuration correct?by default DNS resolver is enabled, im not sure where the ACL where can i check this?
thanks
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That wouldn't affect VPN clients in any way, only the firewall itself.
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Ok..
Also make sure that the DNS resolver is configured with an ACL to allow the OpenVPN client subnet to make DNS queries. how can i check this settings?
thanks
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Services > DNS Resolver, Access Lists tab
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do you use the netBios setting ?
out of the blue
brNP -
@noplan if you are referring to this? then yes
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@jimp looks like DNS resolver is not enabled, can i still proceed to add the ACL or this must be enable first?
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Are you using the DNS Forwarder then?
Or what are the clients using for DNS if not the firewall?
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@jimp DNS forwarders also not enabled.
our clients is using our Windows DNS servers..
configured on here System > General Setting
and here for OpenVPN
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OK so the firewall would not be involved in their DNS at all. The "Block outside DNS" box is about all you can do there other than trying to solve client issues.
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@jimp Ok.
so for the "Block outside DNS" i need to generated a new Windows client configuration with "Block outside DNS" tick to get this setting in effect?
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You can check the box on the server which may help. If it doesn't, then try exporting a fresh client.
If neither one helps then it's something else entirely, most likely not in OpenVPN. Could be on the client or the DNS server, but either way, not pfSense and unlikely to be OpenVPN.
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@jimp Thanks jimp.. I will do some testing first. Thanks!
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@jimp base on my testing the user still encounter the same problem unable to resolves DNS hostname.
my openvpn subnet is 10.50.0.0/22, i noticed when the user is getting 10.50.1.X ip address they encounter the DNS issue.
i dont have any clue where to check next, any advice will be greatly appreciated. Thanks
