"The guards in front of the university are walking up and down."

Translation: Az őrök az egyetem előtt fel és alá sétálnak.

[GyrgyFnyes1]

Az őrök az egyetem előtt fel - alá sétálnak

[Krisbaudi]

Does it mean, that we can't translate UP AND DOWN with FEL ÈS LE?

[postkar]

why is it not felé és alá?

[jsiehler]

Felé is "toward" or "in the direction of", nothing to do with "up." Other than that, fel és alá is just a kind of a fixed expression for "up and down." You may also see it with a hyphen instead: fel-alá

[Gabor111594]

Why not “le-föl”, which is the expression I have grown up with?