diff --git a/fio.1 b/fio.1
index 91fd531..eba748b 100644
--- a/fio.1
+++ b/fio.1
@@ -1216,7 +1216,7 @@
 .BI (net,netsplice)hostname \fR=\fPstr
 The host name or IP address to use for TCP or UDP based IO.
 If the job is a TCP listener or UDP reader, the hostname is not
-used and must be omitted.
+used and must be omitted unless it is a valid UDP multicast address.
 .TP
 .BI (net,netsplice)port \fR=\fPint
 The TCP or UDP port to bind to or connect to.
@@ -1251,13 +1251,14 @@
 hostname must be omitted if this option is used.
 .TP
 .BI (net, pingpong) \fR=\fPbool
-Normal a network writer will just continue writing data, and a network reader
+Normaly a network writer will just continue writing data, and a network reader
 will just consume packages. If pingpong=1 is set, a writer will send its normal
 payload to the reader, then wait for the reader to send the same payload back.
 This allows fio to measure network latencies. The submission and completion
 latencies then measure local time spent sending or receiving, and the
 completion latency measures how long it took for the other end to receive and
-send back.
+send back. For UDP multicast traffic pingpong=1 should only be set for a single
+reader when multiple readers are listening to the same address.
 .TP
 .BI (e4defrag,donorname) \fR=\fPstr
 File will be used as a block donor (swap extents between files)