TCP Links
Introduction Copied
The Geneos TCP Links plugin monitors the active TCP/IP connections to and from the Netprobe host. This plugin is typically used in conjunction with the expect rows feature available with all dataviews, which allows the Gateway to alert when an expected connection is missing or down.
For monitoring of connections to an SLE or LIFFE exchanges, you should use the since it provides more specific detail for this usage.
Note
Beginning Geneos 5.5.x, a TCP Links sampler running on Linux will be able to display TCP/IPÂ connections without dependency on thenet-toolspackage. For Windows and IBM AIX , the TCP Links plugin uses thenetstatcommand, which is part of thenet-toolspackage.
Views Copied
View Copied
The TCP Links plugin produces a single view, where each row in the table represents a either a TCP or a UDP connection. The example below is shown using “expect rows”, indicated by the presence of the Availability column to the far right.
Headline Legend
| Name | Description |
|---|---|
| Total connections | The total number of TCP/IP connections monitored by the plug-in (i.e. those that match the configured monitoring criteria). |
Table Legend
| Name | Description |
|---|---|
| name | Unique connection named, formed by combining elements of the local and remote connection addresses. |
| localAddress | The local host and port being used for the connection. |
| remoteAddress | The remote host and port being used for the connection. |
| sendQueue | Number of bytes in the send queue (waiting to be sent). This column is unavailable for Windows. |
| recvQueue | Number of bytes in the receive queue (waiting to be read). This column is unavailable for Windows. |
| state | The TCP/IP connection state. |
| type | TCP or UDP. |
| Availability | This column will only be present when using the expect rows feature. Possible values are "absent" or "present". |
Plugin Configuration Copied
The TCP Links plugin can be configured to run on any Netprobe host. Configuration is placed in the tcp-links section, and by default no other settings are required.
localPorts Copied
The localPorts section allows users to define a list of ports by which they can filter the view on the localAddress field of a connection. If no ports are defined, then all connections are displayed.
If the localAddress field for a connection contains a specified port (using case sensitive comparison), then the connection passes the filter and is displayed. Otherwise the connection is omitted from the view and hence will not be available in gateway for rules or actions.
Note
Despite the name, the local port can optionally contain a hostname, port or a combination of the two. Syntax is based on Perl-Compatible Regular Expressions (PCRE).
Mandatory: No
remotePorts Copied
The remotePorts section allows users to define a list of ports by which they can filter the view on the remoteAddress field of a connection. If no ports are defined, then all connections are displayed.
If the remoteAddress field for a connection contains a specified port (using case sensitive comparison), then the connection passes the filter and is displayed. Otherwise the connection is omitted from the view and hence will not be available in gateway for rules or actions.
Note
Despite the name, the remote port can optionally contain a hostname, port or a combination of the two. Syntax is based on Perl-Compatible Regular Expressions (PCRE).
Mandatory: No
command Copied
The TCP Links plugin obtains connection information using the netstat utility. The command used to run the utility can be overridden using this setting, which may be useful if access to netstat is protected by access control software.
You can set the command to pbrun netstat -n or sudo netstat -n. The default value is netstat -n.
Note
Beginning Geneos 5.5.x, samplers running on Linux platforms no longer rely on thenet-toolspackage to display TCP/IPÂ links. This option is then ignored on Linux platforms.
Mandatory: No
nameContents Copied
The nameContents setting controls the format of the connection name, as reported in the name column of the data view. If this setting is not specified, the name format defaults to showing the full connection details as described below.
If this setting is specified, then each of the contained settings must be specified with a Boolean value detailing whether this field will be included in the name field. The name format consists of two host+port pairs, separated by a - character. Each pair is constructed according to the following table:
| Host setting value | Port setting value | Host+port format | Example |
|---|---|---|---|
| false | false | <empty> | |
| false | true | :<port> | :80 |
| true | false | <host> | www.google.com |
| true | true | <host>:<port> | www.google.com:80 |
Mandatory: No
Default: <localhost>:<localport>-<remotehost>:<remoteport>
serviceTokens Copied
The serviceTokens setting contains a list of tokens, which are treated in the same manner as for localPorts. This is a legacy setting for backwards compatibility reasons, and should be ignored in favour of using localPorts.
showAllStates Copied
The LISTEN and blank ports can be displayed using the showAllStates checkbox.
Note
- For Windows and AIX platforms, commands will take priority over the
showAllStatescheckbox.- When the
showAllStatescheckbox is enabled, multiple duplicates may appear in thenamecolumn of the dataview. However, these duplicated row names will be automatically renamed to ensure each row is assigned a unique name. Columns can be combined using the First Column feature if needed.