diff --git a/doc/doxygen/lwip.Doxyfile b/doc/doxygen/lwip.Doxyfile
index 9f20830f..31f57657 100644
--- a/doc/doxygen/lwip.Doxyfile
+++ b/doc/doxygen/lwip.Doxyfile
@@ -2080,6 +2080,7 @@ PREDEFINED             = __DOXYGEN__=1 \
                          LWIP_UDP=1 \
                          LWIP_IGMP=1 \
                          LWIP_TCP=1 \
+                         TCP_LISTEN_BACKLOG=1 \
                          LWIP_SNMP=1 \
                          SNMP_USE_NETCONN=1 \
                          SNMP_USE_RAW=1 \