diff --git a/net/sflowtool/Makefile b/net/sflowtool/Makefile
index e637ae85e1ab..9a237f54a1df 100644
--- a/net/sflowtool/Makefile
+++ b/net/sflowtool/Makefile
@@ -1,35 +1,42 @@
 PORTNAME=	sflowtool
 DISTVERSIONPREFIX=	v
-DISTVERSION=	5.08
+DISTVERSION=	6.01
 CATEGORIES=	net
 
 MAINTAINER=	eduardo@FreeBSD.org
 COMMENT=	sFlow capture and sFlow-to-NetFlow conversion tool
 WWW=		https://github.com/sflow/sflowtool/
 
 LICENSE=	InMon
 LICENSE_NAME=	InMon Corp
 LICENSE_FILE=	${WRKSRC}/COPYING
 LICENSE_PERMS=	dist-mirror dist-sell pkg-mirror pkg-sell auto-accept
 
 USES=		autoreconf
 USE_GITHUB=	yes
 GH_ACCOUNT=	sflow
 USE_RC_SUBR=	${PORTNAME}
 
 GNU_CONFIGURE=	yes
 
 PLIST_FILES=	bin/sflowtool
 
 PORTDOCS=	README
 PORTEXAMPLES=	sflowenable
 
 OPTIONS_DEFINE=	DOCS EXAMPLES
 
+.include <bsd.port.options.mk>
+
+# Patch byteswap.h where not available
+.if ${OPSYS} == FreeBSD && ${OSVERSION} < 1301511
+EXTRA_PATCHES=	${PATCHDIR}/extra-patch-src_sflowtool.c
+.endif
+
 post-install:
 	@${MKDIR} ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${PORTDOCS:S|^|${WRKSRC}/|} ${STAGEDIR}${DOCSDIR}
 	@${MKDIR} ${STAGEDIR}${EXAMPLESDIR}
 	${INSTALL_DATA} ${PORTEXAMPLES:S|^|${WRKSRC}/scripts/|} ${STAGEDIR}${EXAMPLESDIR}
 
 .include <bsd.port.mk>
diff --git a/net/sflowtool/distinfo b/net/sflowtool/distinfo
index e092aaaf9da6..40a6a3f22490 100644
--- a/net/sflowtool/distinfo
+++ b/net/sflowtool/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1667822009
-SHA256 (sflow-sflowtool-v5.08_GH0.tar.gz) = 70a1930e1a99077c0cf92d4205c744aaeaadb794927bae8b98463075432b4a8a
-SIZE (sflow-sflowtool-v5.08_GH0.tar.gz) = 79065
+TIMESTAMP = 1679650144
+SHA256 (sflow-sflowtool-v6.01_GH0.tar.gz) = 4cc9f4512a3dcb7da6a970b1de06e3f2fcb599a605e9cfeddd34bd7b9b687f3c
+SIZE (sflow-sflowtool-v6.01_GH0.tar.gz) = 81155
diff --git a/net/sflowtool/files/extra-patch-src_sflowtool.c b/net/sflowtool/files/extra-patch-src_sflowtool.c
new file mode 100644
index 000000000000..b851dddedd14
--- /dev/null
+++ b/net/sflowtool/files/extra-patch-src_sflowtool.c
@@ -0,0 +1,25 @@
+--- src/sflowtool.c.orig	2023-03-23 17:36:24 UTC
++++ src/sflowtool.c
+@@ -29,13 +29,21 @@ extern "C" {
+ #include <inttypes.h>
+ #include <arpa/inet.h>
+ #include <netdb.h>
+-#include <byteswap.h>
++#include <sys/endian.h>
+ #include <getopt.h>
+ 
+ #include "sflow.h" /* sFlow v5 */
+ #include "sflow_v2v4.h" /* sFlow v2/4 */
+ #include "assert.h"
+ #include "sflow_xdr.h" /* sFlow encode */
++
++#define __bswap_16(x) __bswap16(x)
++#define __bswap_32(x) __bswap32(x)
++#define __bswap_64(x) __bswap64(x)
++
++#define bswap_16(x) __bswap16(x)
++#define bswap_32(x) __bswap32(x)
++#define bswap_64(x) __bswap64(x)
+ 
+ #define SPOOFSOURCE 1
+ #define YES 1