https://community.hpe.com/t5/operating-system-linux/equivalen-to-so-bsdcompat/m-p/3638493#M85266 If the target machine discards the message because there is no process reading on the requested port number, it sends an ICMP message to your machine which will cause the next system call on the socket to return<BR /> ECONNREFUSED. Since delivery of ICMP messages is not guarenteed you may not recieve this notification on the first transaction.<BR /><BR /> Remember that your socket must "connected" in order to receive the ICMP errors. Also verify that Linux will return on "unconnected" sockets. This may cause porting problems if your application isn't ready for it, so Alan tells me they've added a SO_BSDCOMPAT flag which can be set for Linux kernels after 2.x<BR /> Thu, 29 Sep 2005 23:34:23 GMT Mugilvannan 2005-09-29T23:34:23Z https://community.hpe.com/t5/operating-system-linux/equivalen-to-so-bsdcompat/m-p/3638492#M85265 SO_BSDCOMPAT is obsolete since the 2.4 kernels and now 2.5 and later<BR />kernels log a warning every time it is used.<BR /><BR />Is there some thing equivalent to SO_BSDCOMPAT that can be used to in order to make sure that "ICMP errors recieved for a UDP socket will not be passed" Thu, 29 Sep 2005 14:18:08 GMT https://community.hpe.com/t5/operating-system-linux/equivalen-to-so-bsdcompat/m-p/3638492#M85265 Srinivas Krishnappa Sha 2005-09-29T14:18:08Z https://community.hpe.com/t5/operating-system-linux/equivalen-to-so-bsdcompat/m-p/3638493#M85266 If the target machine discards the message because there is no process reading on the requested port number, it sends an ICMP message to your machine which will cause the next system call on the socket to return<BR /> ECONNREFUSED. Since delivery of ICMP messages is not guarenteed you may not recieve this notification on the first transaction.<BR /><BR /> Remember that your socket must "connected" in order to receive the ICMP errors. Also verify that Linux will return on "unconnected" sockets. This may cause porting problems if your application isn't ready for it, so Alan tells me they've added a SO_BSDCOMPAT flag which can be set for Linux kernels after 2.x<BR /> Thu, 29 Sep 2005 23:34:23 GMT https://community.hpe.com/t5/operating-system-linux/equivalen-to-so-bsdcompat/m-p/3638493#M85266 Mugilvannan 2005-09-29T23:34:23Z