POST with LWP yields HTTP 302 Not Allowed

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http://www.usps.com/ncsc/lookups/lookup_zip+4.html

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http://www.usps.com/cgi-bin/zip4/zip4inq2

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HTTP/1.0 302 (Found) Not Allowed
Location: http://148.129.65.3:80/fwauthredirect148.129.65.9id000386429
+5
...
Client-Peer: 56.0.78.101:80

Your request is being redirected to :<a href="http://148.129.65.3:80/f
+wauthredirect148.129.65.9id0003864295">here</a>.

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http://www.usps.com:80/cgi-bin/zip4/zip4inq2

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