/* ---------- Pbuf options
This is very inefficient use of memory.
/* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */
#define PBUF_POOL_SIZE 4
/* PBUF_POOL_BUFSIZE: the size
of each pbuf in the pbuf pool. */
#define PBUF_POOL_BUFSIZE 1500
Not sure, but only 4 pbufs might cause the problems you are seeing.
Higher PBUF_POOL_SIZE and
will give you more packet buffers to work with without costing you any
The disadvantage is of course that you will have to handle packets
fragmented into pbuf chains, but in a system with limited RAM that is a
minor inconvenience compared to the amounts of RAM it saves.