If you connect load balancers to your syslog-ng OSE application, syslog-ng OSE identifies every connection that is connected to the load balancers identically by default, regardless of the source IP or the source protocol. Essentially, the load balancer masks the source IP unless you enable Proxy Protocol support for your proxy TLS transport() to inject information about the original connection into the forwarded TCP session.
For further details about the working mechanism behind the Proxy Protocol support on syslog-ng OSE and the configuration details, see the following sections:
Topics:
This section describes how syslog-ng Open Source Edition (syslog-ng OSE) supports the Proxy Protocol.
When using the Proxy Protocol during load balancing, syslog-ng OSE detects the information behind connections connected to the load balancer, then parses the injected information and adds the following macros to every message the comes through the connection later on:
-
PROXY_SRCIP (the source IP of the proxy)
-
PROXY_SRCPORT (the source port of the proxy)
-
PROXY_DSTIP (the destination IP of the proxy)
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PROXY_DSTPORT (the destination port of the proxy)
NOTE: Consider the following about macros and headers:
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When the proxy protocol header is PROXY UNKNOWN, no additional macros are added.
-
When syslog-ng OSE cannot parse a proxy protocol header, the connection is closed:
[2020-11-20T17:33:22.189458] PROXY protocol header received; line='PROXYdsfj'
[2020-11-20T17:33:22.189475] Error parsing PROXY protocol header;
[2020-11-20T17:33:22.189517] Syslog connection closed; fd='13', client='AF_INET(127.0.0.1:51665)', local='AF_INET(0.0.0.0:6666)'
[2020-11-20T17:33:22.189546] Freeing PROXY protocol source driver; driver='0x7fffcba5bcf0'
[2020-11-20T17:33:22.189600] Closing log transport fd; fd='13'
NOTE: Since the driver only implements version 1 of the protocol, it only supports TCP4 and TCP6 connections. TLS connections also supported.
This section provides information about enabling Proxy Protocol support in your network() source options, and an example configuration and output to illustrate how the Proxy Protocol method works in syslog-ng Open Source Edition (syslog-ng OSE).
For more information about the working mechanism of the Proxy Protocol, see The working mechanism behind the Proxy Protocol.
Enabling Proxy Protocol support for your network() source options
Unless you enable Proxy Protocol support for your network() source, syslog-ng OSE identifies every connection that is connected to the load balancers identically by default, regardless of the source IP or the source protocol.
To enable Proxy Protocol for your network() source, set the transport() parameter of your network() source to proxied-tcp or proxied-tls-passthrough, depending on your preference and configuration.
proxied-tls can be used in complex MITM (man in the middle) configurations, where the proxy header is sent encrypted within the same TLS session as the proxied messages.
When you enable Proxy Protocol support for your network() source, you can use the following configuration example with your syslog-ng OSE application.
Configuration
The following code sample illustrates how you can use the Proxy Protocol in your syslog-ng OSE configuration (using the transport() parameter set to proxied-tls-passthrough).
@version: 3.35
source s_tcp_pp {
network (
port(6666)
transport("proxied-tls-passthrough")
tls(
key-file("/certs/certs/server/server.rsa")
cert-file("/certs/certs/server/server.crt")
ca-dir("/certs/certs/CA")
peer-verify("required-trusted")
)
);
};
destination d_file {
file("/var/log/proxy-proto.log" template("$(format-json --scope nv-pairs)\n"));
};
log {
source(s_tcp_pp);
destination(d_file);
};
With this configuration, the Proxy Protocol method will perform injecting the information of the original connection into the forwarded TCP session, based on the working mechanism described in The working mechanism behind the Proxy Protocol.
The following example illustrates how the parsed macros will appear in the output.
Example: Output for the PROXY TCP4 192.168.1.1 10.10.0.1 1111 2222 input header
With the PROXY TCP4 192.168.1.1 10.10.0.1 1111 2222 input header, the output looks like this:
{"SOURCE":"s_tcp_pp","PROXIED_SRCPORT":"1111","PROXIED_SRCIP":"192.168.1.1","PROXIED_IP_VERSION":"4","PROXIED_DSTPORT":"2222","PROXIED_DSTIP":"10.10.0.1","PROGRAM":"TestMsg","MESSAGE":"","LEGACY_MSGHDR":"TestMsg","HOST_FROM":"localhost","HOST":"localhost"}
Note that the macros that syslog-ng OSE adds to the message appear in the output.
Using the nodejs() driver, syslog-ng OSE can receive application logs directly from nodejs applications that use the widespread Winston logging API. The syslog-ng OSE application automatically adds the .nodejs.winston. prefix to the name of the fields the extracted from the message.
To use the nodejs() driver, the scl.conf file must be included in your syslog-ng OSE configuration:
@include "scl.conf"
The nodejs() driver is actually a reusable configuration snippet configured to receive log messages using the network() driver, and process its JSON contents. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of the nodejs configuration snippet on GitHub.
Example: Using the nodejs() driver
The following example uses the default settings of the driver, listening for messages on port 9003 of every IP address of the syslog-ng OSE host.
@include "scl.conf"
source apps { nodejs(); };
The following example listens only on IP address 192.168.1.1, port 9999.
@include "scl.conf"
source apps {
nodejs(
localip(192.168.1.1)
port(9999)
)
};
