diff --git a/fail2ban/server/datetemplate.py b/fail2ban/server/datetemplate.py
index 6309e8eb..34f1ed23 100644
--- a/fail2ban/server/datetemplate.py
+++ b/fail2ban/server/datetemplate.py
@@ -242,7 +242,7 @@ class DatePatternRegex(DateStrptime):
 	_patternRegex = {
 		'a': r"\w{3}", 'A': r"\w+", 'b': r"\w{3}", 'B': r"\w+",
 		'd': r"(?:3[0-1]|[1-2]\d|[ 0]?\d)",
-		'f': r"\d{1,6}", 'H': r"(?:2[0-3]|1\d|[ 0]?\d)",
+		'f': r"(?P<_f>\d{1,6})", 'H': r"(?:2[0-3]|1\d|[ 0]?\d)",
 		'I': r"(?:1[0-2]|[ 0]?\d)",
 		'j': r"(?:36[0-6]3[0-5]\d|[1-2]\d\d|[ 0]?\d\d|[ 0]{0,2}\d)",
 		'm': r"(?:1[0-2]|[ 0]?[1-9])", 'M': r"[0-5]\d", 'p': r"[AP]M",