diff --git a/runtime/lua/vim/filetype.lua b/runtime/lua/vim/filetype.lua
index dd4fe7a138..050e9fe207 100644
--- a/runtime/lua/vim/filetype.lua
+++ b/runtime/lua/vim/filetype.lua
@@ -848,6 +848,8 @@ local extension = {
   NSP = 'natural',
   NSS = 'natural',
   ncf = 'ncf',
+  axs = 'netlinx',
+  axi = 'netlinx',
   nginx = 'nginx',
   ncl = 'nickel',
   nim = 'nim',
diff --git a/test/old/testdir/test_filetype.vim b/test/old/testdir/test_filetype.vim
index a8eda9b424..cf343ead21 100644
--- a/test/old/testdir/test_filetype.vim
+++ b/test/old/testdir/test_filetype.vim
@@ -575,6 +575,7 @@ func s:GetFilenameChecks() abort
     \ 'ncf': ['file.ncf'],
     \ 'neomuttlog': ['/home/user/.neomuttdebug1'],
     \ 'neomuttrc': ['Neomuttrc', '.neomuttrc', '.neomuttrc-file', '/.neomutt/neomuttrc', '/.neomutt/neomuttrc-file', 'Neomuttrc', 'Neomuttrc-file', 'any/.neomutt/neomuttrc', 'any/.neomutt/neomuttrc-file', 'neomuttrc', 'neomuttrc-file'],
+    \ 'netlinx': ['file.axs', 'file.axi'],
     \ 'netrc': ['.netrc'],
     \ 'nginx': ['file.nginx', 'nginxfile.conf', 'filenginx.conf', 'any/etc/nginx/file', 'any/usr/local/nginx/conf/file', 'any/nginx/file.conf'],
     \ 'nickel': ['file.ncl'],