On Mon, Feb 3, 2014 at 11:41 AM, Shane Baker wrote:

I cannot comment on your program termination error.

Regarding UDP being a connectionless protocol, errors may still be returned if the destination host is not reachable. These errors are returned via ICMP. You can see this with Wireshark or a similar tool.

As Baker points out, UDP still runs over IP, which is a routing protocol. If you send packets over UDP, it usually needs to reach a specific destination. If you have no destination in mind, you may broadcast your packets instead, for any receiving interface to receive. To do this, you'd need to set the 'broadcast' option. If you do that, you probably also want to set the do_not_route option as well, to limit how far such messages would broadcast (although, practically speaking, most routers will likely prevent your broadcast packets anyway). - Trey

It's hard to be helpful without more information. Assuming that you are getting a boost::system::system_error thrown in direct response to the send_to() call, I would: 1. Examine your route table to see if there is a problem there. 2. Try using traceroute to your desired address. 3. Try using Wireshark to get more insight. On Mon, Feb 3, 2014 at 12:51 PM, •°o.O sαмι O.o°• wrote:

Thanks to both Baker and Trey, I am not using any asyn.connect or connect method in my program just using "send_to" method " socket.send_to(boost::asio::buffer(send_buf), receiver_endpoint);" My requirement is to send data to multiple specified addresses and one of them might be not available at that time so program should keep sending data to other available addresses but it terminates after throwing exception "host unreachable". Broadcast cannot be used.

On Mon, Feb 3, 2014 at 10:12 PM, Joseph Van Riper < fleeb.fantastique@gmail.com> wrote:

...

On Mon, Feb 3, 2014 at 11:41 AM, Shane Baker wrote:

...

I cannot comment on your program termination error.

Regarding UDP being a connectionless protocol, errors may still be returned if the destination host is not reachable. These errors are returned via ICMP. You can see this with Wireshark or a similar tool.

As Baker points out, UDP still runs over IP, which is a routing protocol. If you send packets over UDP, it usually needs to reach a specific destination.

If you have no destination in mind, you may broadcast your packets instead, for any receiving interface to receive. To do this, you'd need to set the 'broadcast' option. If you do that, you probably also want to set the do_not_route option as well, to limit how far such messages would broadcast (although, practically speaking, most routers will likely prevent your broadcast packets anyway).

- Trey

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On Feb 3, 2014, at 1:41 PM, Marcel Raad wrote:

•°o.O sαмι O.o°• writes:

...

I am not using any asyn.connect or connect method in my program just using "send_to" method " socket.send_to(boost::asio::buffer(send_buf), receiver_endpoint);" My requirement is to send data to multiple specified addresses and one of them might be not available at that time so program should keep sending data to other available addresses but it terminates after throwing exception "host unreachable".

You might want to use the send_to overload taking a boost::system::error_code& parameter which doesn't throw.

That's right. The option is to handle the exception.

But the appropriate mailing list would be boost-users, this mailing list is about developing boost libraries.

We also don't top post and prefer real names in the sender info. See http://www.boost.org/community/policy.html for more info. ___ Rob (Sent from my portable computation engine)