TCP/IP client says CONNECTION REFUSED!

My config seems good.

My computer Ip is 192.168.1.13, with subnet 255.255.255.0 .
My board ip is 192.168.1.11, with default subnet 255.255.255.0 .
I don't have a gateway.

With Wireshark, I get these frames 6 times when I try to connect with a browser:

from 192.168.1.13, in TCP protocol:
ndm-server > ddi-tcp-1 [SYN] Seq=0 win=65535 Len=0 MSS=1460 WS=2 SACK_PERM=1

and then from 192.168.1.11, in TCP protocol:
ddi_tcp-1 > ndm-server [RST] Seq=1 Win=0 Len=0