IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

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IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

Router application services

Updated: August 12, 2026

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Explains how the router starts network daemons, accepts Telnet sessions, assigns a stable source to syslog traffic, and controls HTTP client connections and protocol behavior.

Router application services are functions that

  • start configured server programs for incoming network requests

  • identify outbound management traffic through selected source interfaces, and

  • control client connection, security, response, and protocol settings.

Cisco inetd services

Cisco Internet services process daemon, or Cisco inetd, is a system server process that

  • starts after the system boots

  • listens for configured network services such as Telnet and TFTP, and

  • starts the server program associated with an incoming service request.

Cisco inetd is multithreaded. The router configuration determines which services it monitors.

For example, the tftp server command causes Cisco inetd to listen for TFTP requests.

Cisco inetd service requirement

Install the Telnet RPM before you use the Telnet service or the show cinetd services command.

How Cisco inetd services work

The system manager starts the multithreaded Cisco inetd process after the system boots.

Summary

The process uses these components.

  • Service configuration: Determines which network services Cisco inetd monitors.

  • Service listener: Waits for incoming requests to a registered service.

  • Server program: Handles a request for the associated service.

Workflow

These stages describe how Cisco inetd handles a service request.

  1. A server command, such as tftp server , registers a network service.

  2. Cisco inetd starts listening for requests to the registered service.

  3. A client sends a request to the service.

  4. Cisco inetd starts the server program associated with the requested service.

Result

The server program handles the client request.

What’s next

Use show cinetd services to display registered services and their current connection counts.

Telnet services

A Telnet service is an inbound access function that

  • accepts Telnet connections to the router

  • uses Cisco inetd to start the Telnet server program, and

  • can limit the number of simultaneous users.

Install the Telnet RPM before you enable Telnet or use show cinetd services for the Telnet service.

Enable the Telnet server

Allow inbound Telnet sessions while limiting concurrent connections.

Before you begin

Install the Telnet RPM.

Procedure

  1. Enable the IPv4 Telnet server, set the maximum number of users, and commit the configuration.

    Example:

    Router# configure
Router(config)# telnet ipv4 server max-servers 10
Router(config)# commit

  2. Verify the registered Telnet service and maximum connection count.

    Example:

    Router# show cinetd services

The router accepts up to 10 simultaneous IPv4 Telnet sessions.

Syslog source interfaces

A syslog source interface is a logging setting that

  • selects the interface address used for remote syslog traffic

  • associates traffic from a VRF with one router identity, and

  • helps the remote server identify messages from the same device.

Configure a syslog source interface

Give remote syslog traffic a consistent router source address.

Procedure

  1. Configure and commit the logging source interface.

    Example:

    Router# configure
Router(config)# logging source-interface Loopback2
Router(config)# commit

  2. Verify the logging configuration.

    Example:

    Router# show running-config logging
logging source-interface Loopback2

Remote syslog traffic uses the address assigned to Loopback2.

HTTP client applications

An HTTP client application is a router function that

  • retrieves files from an HTTP server

  • supports connection, response, identity, security, and source settings, and

  • selects the HTTP version and VRF for requests.

The HTTP client application is available by default and is configured in XR configuration mode.

Configuration options

This table describes the HTTP client settings.

Table 1. HTTP client settings

Setting

Function

connection

Sets retry or timeout behavior.

response

Sets how long the client waits for a server response.

secure-verify-host

Verifies that the peer certificate identifies the server. Use http client secure-verify-host disable to disable this check.

secure-verify-peer

Verifies the authenticity of the peer certificate.

source-interface

Selects the source interface for outgoing HTTP connections and supports an IPv4 address, an IPv6 address, or both.

ssl

Selects the SSL configuration for HTTPS requests.

tcp-window-scale

Sets the TCP window-scale factor for high-latency links.

version

Selects HTTP version to be used in HTTP request

  • 1.0: HTTP1.0 will be used for all HTTP requests.

  • 1.1: HTTP1.1 will be used for all HTTP requests.

  • default libcurl: will use HTTP version automatically.

vrf

Specifies the VRF name for HTTP requests.

Configure the HTTP client

Adjust HTTP client behavior for the network and server requirements.

The HTTP client is available by default.

Procedure

  1. Display the available HTTP client settings.

    Example:

    Router# configure
Router(config)# http client ?

  2. Configure a TCP window-scale factor for high-latency links when required.

    Example:

    Router(config)# http client tcp-window-scale 8

  3. Configure the HTTP version when the server requires a specific protocol version.

    Example:

    Router(config)# http client version 1.0
Router(config)# commit

Subsequent HTTP requests use the configured client settings.