---
name: "telnet-probe"
section: "1"
platform: "linux"
package: "pcp"
version: "7.2.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/telnet-probe"
---

# telnet-probe(1)

lightweight telnet-like port probe

## NAME

**telnet-probe** - lightweight telnet-like port probe

## SYNOPSIS

**$PCP\_BINADM\_DIR/telnet-probe** \[**-cv?**\] *host* *port*

## DESCRIPTION

**telnet-probe** allows the [**pmdashping**(1)](/pmdashping/1.md) daemons to establish connections to arbitrary local and remote service-providing daemons so that response time and service availability information can be obtained.

The required *host* and *port* number arguments have the same meaning as their [**telnet**(1)](/telnet/1.md) equivalents.

The **-c** option causes **telnet-probe** to perform a [**connect**(2)](/connect/2.md) only. This skips the [**read**(2)](/read/2.md) and [**write**(2)](/write/2.md) exercise that would otherwise be done after connecting (see below).

Once the telnet connection has been established, **telnet-probe** reads from *stdin* until end-of-file, and writes all the input data to the telnet connection. Next, **telnet-probe** will read from the telnet connection until end-of-file, discarding whatever data it receives. Then **telnet-probe** exits.

To operate successfully, the input passed via **telnet-probe** to the remote service must be sufficient to cause the remote service to close the connection when the last line of input has been processed, e.g. ending with \`\`quit'' when probing SMTP on port 25.

By default **telnet-probe** will not produce any output, unless there is an error in which case a diagnostic message can be displayed (in verbose mode only) and the exit status will be non-zero indicating a failure.

## OPTIONS

The available command line options are:

- **-c**

  Connect only, do not read or write.

- **-v**

  Enable verbose mode.

- **-?**

  Display usage message and exit.

## DIAGNOSTICS

If **telnet-probe** succeeds, then 0 will be returned. If the attempt to establish a connection fails or is terminated, then a non-zero exit status is returned.

## PCP ENVIRONMENT

Environment variables with the prefix **PCP\_** are used to parameterize the file and directory names used by PCP. On each installation, the file */etc/pcp.conf* contains the local values for these variables. The **$PCP\_CONF** variable may be used to specify an alternative configuration file, as described in [**pcp.conf**(5)](/pcp.conf/5.md).

## SEE ALSO

[**PCPIntro**(1)](/PCPIntro/1.md), [**pmdashping**(1)](/pmdashping/1.md), [**pmie**(1)](/pmie/1.md), [**telnet**(1)](/telnet/1.md), [**connect**(2)](/connect/2.md), [**read**(2)](/read/2.md) and [**write**(2)](/write/2.md).