diff options
Diffstat (limited to 'doc/ipv6.html')
| -rw-r--r-- | doc/ipv6.html | 48 |
1 files changed, 0 insertions, 48 deletions
diff --git a/doc/ipv6.html b/doc/ipv6.html deleted file mode 100644 index 67c8e1f..0000000 --- a/doc/ipv6.html +++ /dev/null @@ -1,48 +0,0 @@ -<html> -<head> -<title>Notes on IPv6 Handling in Rsyslog</title> -</head> -<body> -<h1>Notes on IPv6 Handling in Rsyslog</h1> -<p><b>Rsyslog fully* supports sending and receiving syslog messages via both -IPv4 and IPv6.</b> IPv6 is natively supported for both UDP and TCP. However, -there are some options that control handling of IPv6 operations. I thought it is -is a good idea to elaborate a little about them, so that you can probably find -your way somewhat easier.</p> -<p>First of all, you can restrict rsyslog to using IPv4 or IPv6 addresses only -by specifying the -4 or -6 command line option (now guess which one does -what...). If you do not provide any command line option, rsyslog uses IPv4 and -IPv6 addresses concurrently. In practice, that means the listener binds to both -addresses (provided they are configured). When sending syslog messages, rsyslog -uses IPv4 addresses when the receiver can be reached via IPv4 and IPv6 addresses -if it can be reached via IPv6. If it can be reached on either IPv4 and v6, -rsyslog leaves the choice to the socket layer. The important point to know is -that it uses whatever connectivity is available to reach the destination.</p> -<p><b>There is one subtle difference between UDP and TCP.</b> With the new -IPv4/v6 ignorant code, rsyslog has potentially different ways to reach -destinations. The socket layer returns all of these paths in a sorted array. -For TCP, rsyslog loops through this array until a successful TCP connect can be -made. If that happens, the other addresses are ignored and messages are sent via -the successfully-connected socket.</p> -<p>For UDP, there is no such definite success indicator. Sure, the socket layer -may detect some errors, but it may not notice other errors (due to the -unreliable nature of UDP). By default, the UDP sender also tries one entry after -the other in the sorted array of destination addresses. When a send fails, the -next address is tried. When the send function finally succeeds, rsyslogd assumes -the UDP packet has reached its final destination. However, if rsyslogd is -started with the "-A" (capital A!) was given on the command line, rsyslogd will -continue to send messages until the end of the destination address array is -reached. This may result in duplicate messages, but it also provides some -additional reliability in case a message could not be received. You need to be -sure about the implications before applying this option. In general, it is NOT -recommended to use the -A option.</p> -<p><i><b>*</b>rsyslog does not support RFC 3195 over IPv6. The reason is that -the RFC 3195 library, <a href="http://www.liblogging.org/">liblogging</a>, -supports IPv4, only. Currently, there are no plans to update either rsyslog to -another RFC 3195 stack or update liblogging. There is simply no demand for 3195 -solutions.</i></p> -<p><font size="2">Last Updated: 2007-07-02<br> -Copyright © 2007 by Rainer Gerhards, released under the GNU GPL V2 or later.</font></p> - -</body> -</html> |