So when configure .htaccess file for Apache httpd server, you should ignore those buggy IE browser or non-supported browsers. Here is my .htaccess file:
# Netscape 4.x or IE 5.5/6.0
BrowserMatch ^Mozilla/4 no-gzip
# IE 5.5 and IE 6.0 have bugs! Ignore them until IE 7.0+
BrowserMatch \bMSIE\s7 !no-gzip
# IE 6.0 after SP2 has no gzip bugs!
BrowserMatch \bMSIE.*SV !no-gzip
# Sometimes Opera pretends to be IE with "Mozila/4.0"
BrowserMatch \bOpera !no-gzip
Header append Vary User-Agent