用ping吧,如果ping你的DNS服务器成功就表明连通了。
/////////////////////////////fun declare
function long inet_addr(ref string addr) library "wsock32.dll"
function long IcmpCloseHandle(long IcmpHandle) library "icmp.dll"
function long IcmpSendEcho (long IcmpHandle,long DestinationAddress,string requestData,integer requestSize,long requestOption,ref ust_icmp_echo_reply replyBuffer,long replySize,long timeout ) library "icmp.dll"
function long IcmpCreateFile() library "icmp.dll"
////////////////////////////structure declare ust_icmp_echo_reply:
ulong address
ulong status
ulong roundtriphome
uint datasize
uint reserved
ulong datapointer
ust_ip_option_information
char data[250]
////////////////////////////////////declare structure ust_ip_option_information:
char ttl
char tos
char flags
char optionssize
long optionsdata
////////////////////////////////////fun
ulong lul_NetAddress
long ll_hFile,ll_ret
string ls_Message=Space(20)
ust_icmp_echo_reply preturn
lul_NetAddress=inet_addr(as_IPAddr)
IF lul_NetAddress=-1 THEN RETURN FALSE
ll_hFile=IcmpCreateFile()
IF ll_hFile = 0 THEN RETURN FALSE
ll_ret=IcmpSendEcho(ll_hFile,lul_NetAddress,ls_Message,Len(ls_Message),0,preturn,282,200)
IcmpCloseHandle(ll_hfile)