https://jaaadesign.nl/en/blog/speed-up-wordpress-multisite/ (test the .htaccess file)
AddOutputFilterByType DEFLATE text / html text / plain text / xml
AddOutputFilterByType DEFLATE text / css
AddOutputFilterByType DEFLATE application / x - javascript application / javascript application / ecmascript
AddOutputFilterByType DEFLATE application / rss + xml
< IfModule mod_mime.c >
AddType text / css.css
AddType application / x - javascript.js
AddType text / x - component.htc
AddType text / html.html.htm
AddType text / richtext.rtf.rtx
AddType image / svg + xml.svg.svgz
AddType text / plain.txt
AddType text / xsd.xsd
AddType text / xsl.xsl
AddType text / xml.xml
AddType video / asf.asf.asx.wax.wmv.wmx
AddType video / avi.avi
AddType image / bmp.bmp
AddType application / java.class
AddType video / divx.divx
AddType application / msword.doc.docx
AddType application / vnd.ms - fontobject.eot
AddType application / x - msdownload.exe
AddType image / gif.gif
AddType application / x - gzip.gz.gzip
AddType image / x - icon.ico
AddType image / jpeg.jpg.jpeg.jpe
AddType application / vnd.ms - access.mdb
AddType audio / midi.mid.midi
AddType video / quicktime.mov.qt
AddType audio / mpeg.mp3.m4a
AddType video / mp4.mp4.m4v
AddType video / mpeg.mpeg.mpg.mpe
AddType application / vnd.ms - project.mpp
AddType application / x - font - otf.otf
AddType application / vnd.oasis.opendocument.database.odb
AddType application / vnd.oasis.opendocument.chart.odc
AddType application / vnd.oasis.opendocument.formula.odf
AddType application / vnd.oasis.opendocument.graphics.odg
AddType application / vnd.oasis.opendocument.presentation.odp
AddType application / vnd.oasis.opendocument.spreadsheet.ods
AddType application / vnd.oasis.opendocument.text.odt
AddType audio / ogg.ogg
AddType application / pdf.pdf
AddType image / png.png
AddType application / vnd.ms - powerpoint.pot.pps.ppt.pptx
AddType audio / x - realaudio.ra.ram
AddType application / x - shockwave - flash.swf
AddType application / x - tar.tar
AddType image / tiff.tif.tiff
AddType application / x - font - ttf.ttf.ttc
AddType audio / wav.wav
AddType audio / wma.wma
AddType application / vnd.ms - write.wri
AddType application / vnd.ms - excel.xla.xls.xlsx.xlt.xlw
AddType application / zip.zip < /IfModule>
< IfModule mod_expires.c >
ExpiresActive On
ExpiresByType text / css A31536000
ExpiresByType application / x - javascript A31536000
ExpiresByType text / x - component A31536000
ExpiresByType text / html A3600
ExpiresByType text / richtext A3600
ExpiresByType image / svg + xml A3600
ExpiresByType text / plain A3600
ExpiresByType text / xsd A3600
ExpiresByType text / xsl A3600
ExpiresByType text / xml A3600
ExpiresByType video / asf A31536000
ExpiresByType video / avi A31536000
ExpiresByType image / bmp A31536000
ExpiresByType application / java A31536000
ExpiresByType video / divx A31536000
ExpiresByType application / msword A31536000
ExpiresByType application / vnd.ms - fontobject A31536000
ExpiresByType application / x - msdownload A31536000
ExpiresByType image / gif A31536000
ExpiresByType application / x - gzip A31536000
ExpiresByType image / x - icon A31536000
ExpiresByType image / jpeg A31536000
ExpiresByType application / vnd.ms - access A31536000
ExpiresByType audio / midi A31536000
ExpiresByType video / quicktime A31536000
ExpiresByType audio / mpeg A31536000
ExpiresByType video / mp4 A31536000
ExpiresByType video / mpeg A31536000
ExpiresByType application / vnd.ms - project A31536000
ExpiresByType application / x - font - otf A31536000
ExpiresByType application / vnd.oasis.opendocument.database A31536000
ExpiresByType application / vnd.oasis.opendocument.chart A31536000
ExpiresByType application / vnd.oasis.opendocument.formula A31536000
ExpiresByType application / vnd.oasis.opendocument.graphics A31536000
ExpiresByType application / vnd.oasis.opendocument.presentation A31536000
ExpiresByType application / vnd.oasis.opendocument.spreadsheet A31536000
ExpiresByType application / vnd.oasis.opendocument.text A31536000
ExpiresByType audio / ogg A31536000
ExpiresByType application / pdf A31536000
ExpiresByType image / png A31536000
ExpiresByType application / vnd.ms - powerpoint A31536000
ExpiresByType audio / x - realaudio A31536000
ExpiresByType image / svg + xml A31536000
ExpiresByType application / x - shockwave - flash A31536000
ExpiresByType application / x - tar A31536000
ExpiresByType image / tiff A31536000
ExpiresByType application / x - font - ttf A31536000
ExpiresByType audio / wav A31536000
ExpiresByType audio / wma A31536000
ExpiresByType application / vnd.ms - write A31536000
ExpiresByType application / vnd.ms - excel A31536000
ExpiresByType application / zip A31536000 < /IfModule>
< IfModule mod_setenvif.c >
BrowserMatch ^ Mozilla / 4 gzip - only - text / html
BrowserMatch ^ Mozilla / 4\.0[678] no - gzip
BrowserMatch\ bMSIE!no - gzip!gzip - only - text / html
BrowserMatch\ bMSI[E] !no - gzip!gzip - only - text / html < /IfModule>
< IfModule mod_headers.c >
Header append Vary User - Agent env = !dont - vary < /IfModule> < IfModule mod_filter.c >
AddOutputFilterByType DEFLATE text / css application / x - javascript text / x - component text / html text / richtext image / svg + xml text / plain text / xsd text / xsl text / xml image / x - icon < /IfModule>
< FilesMatch "\.(asf|asx|wax|wmv|wmx|avi|bmp|class|divx|doc|docx|eot|exe|gif|gz|gzip|ico|jpg|jpeg|jpe|mdb|mid|midi|mov|qt|mp3|m4a|mp4|m4v|mpeg|mpg|mpe|mpp|otf|odb|odc|odf|odg|odp|ods|odt|ogg|pdf|png|pot|pps|ppt|pptx|ra|ram|svg|svgz|swf|tar|tif|tiff|ttf|ttc|wav|wma|wri|xla|xls|xlsx|xlt|xlw|zip|ASF|ASX|WAX|WMV|WMX|AVI|BMP|CLASS|DIVX|DOC|DOCX|EOT|EXE|GIF|GZ|GZIP|ICO|JPG|JPEG|JPE|MDB|MID|MIDI|MOV|QT|MP3|M4A|MP4|M4V|MPEG|MPG|MPE|MPP|OTF|ODB|ODC|ODF|ODG|ODP|ODS|ODT|OGG|PDF|PNG|POT|PPS|PPT|PPTX|RA|RAM|SVG|SVGZ|SWF|TAR|TIF|TIFF|TTF|TTC|WAV|WMA|WRI|XLA|XLS|XLSX|XLT|XLW|ZIP)$" >
< IfModule mod_headers.c >
Header set Pragma "public"
Header append Cache - Control "public, must-revalidate, proxy-revalidate"
Header set Access - Control - Allow - Origin "*" < /IfModule>
< /FilesMatch>
< IfModule mod_deflate.c >
< IfModule mod_headers.c >
Header append Vary User - Agent env = !dont - vary < /IfModule>
AddOutputFilterByType DEFLATE text / css text / x - component application / x - javascript application / javascript text / javascript text / x - js text / html text / richtext image / svg + xml text / plain text / xsd text / xsl text / xml image / x - icon application / json < IfModule mod_mime.c > #DEFLATE by extension
AddOutputFilter DEFLATE js css htm html xml
< /IfModule> < /IfModule >