-# Matches the first two things a server should say. Most servers say
-# something after 220, even though they don't have to, and it usually
-# includes the string "ftp" (l7-filter is case insensitive).
-# This includes proftpd, vsftpd, wuftpd, warftpd, pureftpd, Bulletproof
-# FTP Server, and whatever ftp.microsoft.com uses. Just in case, the next
-# thing the server sends is a 331. All the above servers also send
-# something including "password" after this code.
+# Handles the first two things a server should say:
+#
+# First, the server says it's ready by sending "220". Most servers say
+# something after 220, even though they don't have to, and it usually
+# includes the string "ftp" (l7-filter is case insensitive). This
+# includes proftpd, vsftpd, wuftpd, warftpd, pureftpd, Bulletproof FTP
+# Server, and whatever ftp.microsoft.com uses. Almost all servers use only
+# ASCII printable characters between the "220" and the "FTP", but non-English
+# ones might use others.
+#
+# The next thing the server sends is a 331. All the above servers also
+# send something including "password" after this code. By default, we
+# do not match on this because it takes another packet and is more work
+# for regexec.
+