diff --git a/src/include/ipxe/tcp.h b/src/include/ipxe/tcp.h
index 68bb899a..197712b1 100644
--- a/src/include/ipxe/tcp.h
+++ b/src/include/ipxe/tcp.h
@@ -257,10 +257,6 @@ struct tcp_options {
 /** Smallest port number on which a TCP connection can listen */
 #define TCP_MIN_PORT 1
 
-/* Some IOB constants */
-#define MAX_IOB_LEN	1500
-#define MIN_IOB_LEN	MAX_HDR_LEN + 100 /* To account for padding by LL */
-
 /**
  * Maxmimum advertised TCP window size
  *