It is very important topic for various examinations as Questions do come from this topic regularly. So You should know about the Important International Boundary Lines between various countries.
Durand line: The boundary line between Pakistan and Afghanistan
Radcliffe line: The boundary line between India and Pakistan
Macmohan line: The boundary line between china and India
17th Parallel ‐ The line which defines the boundary between North Vietnam and South Vietnam before the two were united.
24th Parallel ‐ The boundary line between India and Myanmar
38th parallel: The boundary line between North and South Korea
49th Parallel ‐ It is the boundary line between the United States of America and Canada.
Oder–Neisse line : The boundary line between Germany and Poland
Hindenburg Line: The boundary line between Germany and Poland
Maginot Line: The boundary line between France and Germany