diff --git a/port/ethernetif.c b/port/ethernetif.c
index f5aed1b..3b9a310 100644
--- a/port/ethernetif.c
+++ b/port/ethernetif.c
@@ -13,7 +13,7 @@
 #define IFNAME0 'e'
 #define IFNAME1 'n'
 
-#define ETH_RX_BUF_COUNT 4
+#define ETH_RX_BUF_COUNT 2
 #define ETH_TX_BUF_COUNT 2
 /* buf size should be at least ETH_MAX_PACKET_SIZE */
 #define ETH_RX_BUF_SIZE ETH_MAX_PACKET_SIZE
diff --git a/port/lwipopts.h b/port/lwipopts.h
index 2b74a58..b1ff645 100644
--- a/port/lwipopts.h
+++ b/port/lwipopts.h
@@ -11,59 +11,50 @@
 // #define ETHARP_DEBUG LWIP_DBG_ON
 
 #define NO_SYS 1
-
-// Core locking
 #define SYS_LIGHTWEIGHT_PROT 0
-
-// Memory options
-#define MEM_ALIGNMENT 4
-#define MEM_SIZE (10 * 1024)  // 4KB of RAM for lwIP heap
-
-// Pbuf options
-#define PBUF_POOL_SIZE 24      // Enough for bursts
-#define PBUF_POOL_BUFSIZE 600  // ~500 byte typical packet + header
-
-// TCP options
-#define LWIP_TCP 1
-#define TCP_MSS 1460
-#define TCP_SND_BUF (2 * TCP_MSS)
-
-// UDP options
-#define LWIP_UDP 1
-
-// ICMP options
-#define LWIP_ICMP 1
-
-// DHCP options
-#define LWIP_DHCP 1
-
-// Checksum options
-// #define CHECKSUM_GEN_IP               0
-// #define CHECKSUM_GEN_UDP              0
-// #define CHECKSUM_GEN_TCP              0
-// #define CHECKSUM_CHECK_IP             0
-#define CHECKSUM_CHECK_UDP 0
-// #define CHECKSUM_CHECK_TCP            0
-// #define LWIP_CHECKSUM_ON_COPY         1
-
 #define LWIP_NETCONN 0
 #define LWIP_SOCKET 0
 
-// Statistics
-#define LWIP_STATS 1
-#define LINK_STATS 1
-// #define MIB2_STATS 1
+// Memory options
+#define MEM_ALIGNMENT 4
+#define MEM_SIZE (4 * 1024)
 
+// Pbuf options
+#define PBUF_POOL_SIZE 4
+#define PBUF_POOL_BUFSIZE 1524
+
+#define MEMP_NUM_PBUF 8  // default 16
+
+// TCP options
+#define LWIP_TCP 1
+#define TCP_MSS 536
+#define TCP_SND_BUF (2 * TCP_MSS)
+#define TCP_WND (2 * TCP_MSS)
+#define TCP_QUEUE_OOSEQ 0
+
+#define LWIP_UDP 1
+#define MEMP_NUM_UDP_PCB 2  // # of concurrent UDP "connections"
+#define LWIP_ICMP 1
+
+#define LWIP_DHCP 1
 #define LWIP_HTTPD 1
-// Use a read-only filesystem populated by makefsdata
-// #define HTTPD_FSDATA_FILE "fsdata_custom.c"
 #define LWIP_HTTPD_FS_SUPPORT 1
 #define HTTPD_USE_CUSTOM_FSDATA 1
 
 #define LWIP_NETIF_HOSTNAME 1
 #define LWIP_NETIF_LINK_CALLBACK 1
 #define LWIP_NETIF_STATUS_CALLBACK 1
+#define LWIP_SUPPORT_CUSTOM_PBUF 1  // for zero-copy
 
-#define LWIP_SUPPORT_CUSTOM_PBUF 1
+#define CHECKSUM_GEN_IP 1
+#define CHECKSUM_GEN_UDP 1
+#define CHECKSUM_GEN_TCP 1
+#define CHECKSUM_CHECK_IP 1
+#define CHECKSUM_CHECK_UDP 1
+#define CHECKSUM_CHECK_TCP 1
+#define LWIP_CHECKSUM_ON_COPY 0
+
+#define LWIP_STATS 1
+#define LINK_STATS 1
 
 #endif /* __LWIPOPTS_H__ */