^start of line
Failed password forthe literal text Failed password for (case sensitive) Non-Capturing Group(?: invalid user)? ?repeats the group contents below at most once:
invalid userthe literal text invalid user (case sensitive) the literal (3210 / 408 / 2016)
.+any Unicode character (except for line terminators), repeated at least once
from the literal text from (case sensitive) Group ipAddress(?<ipAddress>(?:\d{1,3}\.){3}\d{1,3}) Non-Capturing Group(?:\d{1,3}\.){3} {3}repeats the group contents below exactly 3 times:
\d{1,3}a Unicode decimal digit, repeated between 1 and 3 times
\.the literal . (4610 / 568 / 2E16)
\d{1,3}a Unicode decimal digit, repeated between 1 and 3 times
port the literal text port (case sensitive) \d{1,5}a Unicode decimal digit, repeated between 1 and 5 times
sshthe literal text ssh (case sensitive) \d?optionally matches a Unicode decimal digit
$end of line
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string