;begin
format PE console ;just to see the console and know if app is still running
include '%fasminc%\win32ax.inc'
main:
;code
invoke WSAStartup,0101h,wsa
invoke socket,AF_INET,SOCK_STREAM,0
mov [sock],eax
mov eax,23
xchg ah,al ;Got it from quenatton example, but I don't understand this well, except that is exchanges ah and al, but for what?
mov [saddr.sin_port],ax
mov [saddr.sin_addr],0 ;Here I put 0 so any IP will be accepted, but for the client part I don't know how to use IP address. In what format should it be passed to sin_addr? Could you give me a example please? (not that that comes with quenatton, but something simple like IP number stored somewhere with db or dd, I don't know...)
mov [saddr.sin_family],AF_INET
invoke bind,[sock],saddr,sizeof.sockaddr
invoke listen,[sock],1
invoke accept,[sock],0,0
mov [sock2],eax
invoke send,[sock2],msg,endmsg-msg,0
invoke closesocket,[sock2]
invoke closesocket,[sock]
ret
;end of code

;data
wsa WSADATA
sock dd 0
sock2 dd 0
saddr sockaddr_in
msg db 'hi',0
endmsg:
;end of data
.end main
;eof
    

And with the help of FASM's macros one can do multi-platform programming by simply using macros and defining symbols that will do the compilation for each platform.
I'll sticky with FASM by now and forget HLL's for a while...