My Spanish ISP (Vodafone ES) doesn't block external DNS at the ISP level. However, the router they give you:
1) Blocks outgoing DNS requests from the internal network by default. This can be disabled.
2) Doesn't let you specify any other than Vodafone's DNS servers on the DHCP Server configuration. This cannot be changed.
I'll let you decide whether this is blocking or not...
My Spanish ISP (Vodafone ES) doesn't block external DNS at the ISP level. However, the router they give you:
1) Blocks outgoing DNS requests from the internal network by default. This can be disabled.
2) Doesn't let you specify any other than Vodafone's DNS servers on the DHCP Server configuration. This cannot be changed.
I'll let you decide whether this is blocking or not...