diff --git a/src/add-ons/mail_daemon/inbound_protocols/pop3/pop3.cpp b/src/add-ons/mail_daemon/inbound_protocols/pop3/pop3.cpp
index 55c3d0c08e..e3f13ebad0 100644
--- a/src/add-ons/mail_daemon/inbound_protocols/pop3/pop3.cpp
+++ b/src/add-ons/mail_daemon/inbound_protocols/pop3/pop3.cpp
@@ -640,7 +640,7 @@ POP3Protocol::ReceiveLine(BString &line)
 status_t
 POP3Protocol::SendCommand(const char *cmd)
 {
-	if (fSocket < 0 || fSocket > FD_SETSIZE)
+	if (fSocket < 0 || fSocket >= FD_SETSIZE)
 		return B_FILE_ERROR;
 
 	//printf(cmd);