UDP socket loopback problem while IP != 127.0.0.1

===================== RTOS - INTEGRITY Target - PowerPC 8260 Target IP Address - 10.1.1.1 Host: Microsoft IP Professional Host IP Address - 10.1.1.75 =====================

----------------- UDP Sockets

-----------------

socket1: ip1, port1 // on Target socket2: ip2, port2 // on Target socket3: ip3, port3 // on Host

ip1 == ip2 port1 != port2

ip1 != ip3 // ip3 == 10.1.1.75

---------------------------------- From Target to Target sendto () // From socket1 to (ip2, port2) - Target recvfrom() // On socket2 - Target

---------------------------------

Situation 1. ip1 == ip2 == 127.0.0.1 (The standard IP address used for a loopback network connection) It works fine. A message has been sent by using sendto() via socket1, and it has been received by using recvfrom() via socket2.

Situation 2. ip1 == ip2 == 10.1.1.1 (Target IP Address) It doesn't work. A message has been sent by using sendto() via socket1, but recvfrom() is waiting for a message (blocked) via socket2.

--- What could be reason for that?

--- Problem with a DNS server?

Additional information.

1. gethostbyname() doesn't work on the target, i.e., doesn't produce its IP Address 10.1.1.1

1. Similar UDP socket loopback program works fine on PC:
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2. Target -> Host ---------------------------------- From Target to Host ip1 = 10.1.1.1; ip3 = 10.1.1.75 sendto () // From socket1 to (ip3, port3) - Target recvfrom() // On socket3 - Host --------------------------------- It works fine. A message has been sent by using sendto() via socket1, and it has been received by using recvfrom() via socket3.

1. The question was asked on news:comp.unix.programmer in thread
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   about a month ago too.