1 files changed, 1 insertions, 1 deletions
diff --git a/urlmatch.c b/urlmatch.c
index 33a2ccd..03ad3f3 100644
--- a/urlmatch.c
+++ b/urlmatch.c
@@ -5,7 +5,7 @@
 #define URL_DIGIT "0123456789"
 #define URL_ALPHADIGIT URL_ALPHA URL_DIGIT
 #define URL_SCHEME_CHARS URL_ALPHADIGIT "+.-"
-#define URL_HOST_CHARS URL_ALPHADIGIT ".-[:]" /* IPv6 literals need [:] */
+#define URL_HOST_CHARS URL_ALPHADIGIT ".-_[:]" /* IPv6 literals need [:] */
 #define URL_UNSAFE_CHARS " <>\"%{}|\\^`" /* plus 0x00-0x1F,0x7F-0xFF */
 #define URL_GEN_RESERVED ":/?#[]@"
 #define URL_SUB_RESERVED "!$&'()*+,;="