diff --git a/doc/man/knot.conf.5in b/doc/man/knot.conf.5in
index f9c2822a1a..385ce576c4 100644
--- a/doc/man/knot.conf.5in
+++ b/doc/man/knot.conf.5in
@@ -297,7 +297,7 @@ the connection is closed by the server.
 .sp
 Maximum time (in milliseconds) to receive or send one DNS message over an inbound
 TCP connection. It means this limit applies to normal DNS queries and replies,
-incoming DDNS, and outgoing zone transfers. The timeout is measured since some
+incoming DDNS, and \fBoutgoing zone transfers\fP\&. The timeout is measured since some
 data is already available for processing.
 Set to 0 for infinity.
 .sp
diff --git a/doc/reference.rst b/doc/reference.rst
index 222b4d2539..4fb0615943 100644
--- a/doc/reference.rst
+++ b/doc/reference.rst
@@ -288,7 +288,7 @@ tcp-io-timeout
 
 Maximum time (in milliseconds) to receive or send one DNS message over an inbound
 TCP connection. It means this limit applies to normal DNS queries and replies,
-incoming DDNS, and outgoing zone transfers. The timeout is measured since some
+incoming DDNS, and **outgoing zone transfers**. The timeout is measured since some
 data is already available for processing.
 Set to 0 for infinity.