# APL(NARS) 50 chars, 100 bytes

    {'...'≢⍵∼⎕D:0⋄4≠≢w←⍵⊂⍨⍵≠'.':0⋄w≢⍕¨m←⍎¨w:0⋄256>⌈/m}

test:

      p←{'...'≢⍵∼⎕D:0⋄4≠≢w←⍵⊂⍨⍵≠'.':0⋄w≢⍕¨m←⍎¨w:0⋄256>⌈/m}
      {⍞←'[',⍵,'=',(p ⍵),']'⋄⍬}¨a 
    [1.160.10.240= 1 ][192.001.32.47= 0 ][1.2.3.= 0 ][0.00.10.255= 0 ][1.2.$.4= 0 ][255.160.0.34= 1 ][.1.1.1= 0 ][1..1.1.1= 0 ][1.1.1.-0= 0 ][.1.1.+1= 0 ][1 1 1 1= 0 ][1= 0 ][10.300.4.0= 0 ][10.4F.10.99= 0 ][fruit loops= 0 ][1.2.3.4.5= 0 ][0.0.0.0= 1 ][0.0 0.0.= 0 ][1.23..4= 0 ][1:1:1:1:1:1:1:1= 0 ]