How does the open border agreement in the EU work in countries that border non-EU states, such as Russia

How does the open border agreement in the EU work in countries that border non-EU states, such as Russia?
For example, is there control on the side bordering a non-EU state? Or is the border control that of the country that is non-EU?
Other - Europe - 1 Answers
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There is a normal border between a EU and a non EU state, with customs and passport control on both sides. The fact that one of the country is a EU member doesn't change anything to the way the border is held on both sides.