[jboss-jira] [JBoss JIRA] (JGRP-1880) UDP.ip_ttl is ignored and is always 1

[Bela Ban (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12998698#comment-12998698 ] 

Bela Ban edited comment on JGRP-1880 at 9/23/14 6:38 AM:
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Class {{DatagramChannel}} has the ability to set {{IP_MULTICAST_TTL}} as an option. Investigate whether we can use a {{DatagramChannel}} instead of a {{DatagramSocket}}. Perhaps we can create a {{DatagramChannel}}, but then call {{DatagramChannel.socket()}} to simply use the underlying {{DatagramSocket}} instead.
Example:
{code}
DatagramChannel ch=DatagramChannel.open();
ch.setOption(StandardSocketOptions.IP_MULICAST_TTL, 8); // sets TTL to 8
DatagramSocket sock=ch.socket()
// use sock
{code}


was (Author: belaban):
Class {{DatagramChannel}} has the ability to set {{IP_MULICAST_TTL}} as an option. Investigate whether we can use a {{DatagramChannel}} instead of a {{DatagramSocket}}. Perhaps we can create a {{DatagramChannel}}, but then call {{DatagramChannel.socket()}} to simply use the underlying {{DatagramSocket}} instead.
Example:
{code}
DatagramChannel ch=DatagramChannel.open();
ch.setOption(StandardSocketOptions.IP_MULICAST_TTL, 8); // sets TTL to 8
DatagramSocket sock=ch.socket()
// use sock
{code}

> UDP.ip_ttl is ignored and is always 1
> -------------------------------------
>
>                 Key: JGRP-1880
>                 URL: https://issues.jboss.org/browse/JGRP-1880
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.6
>
>
> Since we switched from using a {{MulticastSocket}} for sending of multicast packets to a {{DatagramSocket}}, the time-to-live (TTL) of a packet is always {{1}}. The reason is that method {{setTimeToLive()}} only exists in {{MulticastSocket}}, but not in {{DatagramSocket}}.
> We cannot revert the code and use a {{MulticastSocket}} to send multicasts, as this won't reveal the real IP address of the sender, but only the multicast address, and the real address is needed to drop packets at the _transport level_.
> Investigate whether we could use reflection to get the {{DatagramSocketImpl}} and call {{setTimeToLive()}}.



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