Server Fault
Server Fault

Questions tagged [telnet]

For questions about Telnet, a protocol for bidirectional interactive text-oriented communication with remote hosts via virtual terminals. It is defined in RFC 854.

Telnet is a protocol for bidirectional interactive text-oriented communication with remote hosts via virtual terminals. It is defined in RFC 854.

Telnet provides no inherent security and so is becoming less commonly supported. On modern UNIX-like systems it is usually replaced with more secure and flexible SSH protocol.

336 questions
330
votes
9 answers

Check if port is open or closed on a Linux server?

How can I check if a port is listening on a Linux server?
James Anderson
  • 3,467
52
votes
6 answers

How to check that an OpenVPN server is listening on a remote port without using OpenVPN client?

I need to check that an OpenVPN (UDP) server is up and accessible on a given host:port. I only have a plain Windows XP computer with no OpenVPN client (and no chance to install it) and no keys needed to connect to the server - just common WinXP…
Ivan
  • 3,432
44
votes
10 answers

keyboard shortcut to quit 'telnet'

on Windows XP/server 2003 When telnet some remote host on a specified port, after connection established, sometimes press ctrl+] doesn't quit. Is there any command can quit instead of just close the command line window? Thanks. EDIT: But sometimes…
Stan
  • 1,387
31
votes
7 answers

something like telnet, but "listen on", not "connect to"

With the telnet program one can connect to any TCP port on any host, but is there a way to listen on some port on current host? i.e. 1) on host a: telnet listen 12345 2) on host b: telnet host_a 12345 I don't want any service behind the listening…
user1020218
  • 311
26
votes
9 answers

Is packet sniffing for passwords on a fully switched network really a concern?

I administer a number of linux servers that require telnet access for users. Currently the user's credentials are stored locally on each server and the passwords tend to be very weak and there is no requirement for them to be changed. The logons…
mmcg
  • 380
25
votes
3 answers

How to test a connection without telnet?

I'm trying to test whether machine A can connect to machine B on certain ports. The sysadmins of machine A have seen fit to remove the telnet command. What would be a convenient replacement? Machine A is CentOS.
Steve Bennett
  • 6,000
20
votes
3 answers

How to kill a telnet client with rlwrap since ^] does not work?

When I use telnet with rlwrap it looks like there is no way to kill the client. Am I missing something here or I really have to kill the process with the kill command?
chrisapotek
  • 595
17
votes
1 answer

How to determine if google public stun server is alive or usable?

I have seen a lot of of WebRTC client libraries using public STUN server like below: "stun.l.google.com:19302", "stun1.l.google.com:19302", "stun2.l.google.com:19302", …
forestclown
  • 1,015
17
votes
2 answers

invoking telnet from two different interfaces

I use telnet to test email server connectivity between servers. My server has two interfaces, I'd like to telnet over each. Basically I'd like to choose source (one of my local ip addresses) AND destination when using telnet. Is this possible?
RussellBallestrini
  • 321
16
votes
1 answer

How to check postfix server using telnet

I have postfix email server on Ubuntu 11.04 version. I upgraded installed packages using the following command sudo aptitude update && sudo aptitude safe-upgrade Once I update those packages, I couldn't connect my email from my client machine. So I…
Smith Dwayne
  • 269
16
votes
9 answers

Send an email with an attached file using telnet or netcat

I often use telnet or netcat to connect smtp servers to send an email as a test. Does anyone know how you would send an email using telnet or netcat but attach a file as well? There are probably better ways, but I still want to know :-) I would…
Kyle Brandt
  • 85,693
16
votes
2 answers

Verify connectivity to a server on a UDP port

I want to know if a HP-UX machine can communicate to a remote machine (which I don't have control over) on a particular port using UDP. I tried telnet, but it doesn't look like it supports UDP. I would use netcat, but I was unable to find any…
skinp
  • 789
14
votes
3 answers

Contacting DNS server via command line interface

So, we are on the DNS chapter in our class, and I was wondering if there's any way possible though which I can connect to a DNS server on port 53 via command line interface (i.e Telnet or netcat) like we do for SMTP or HTTP or POP on their specific…
Jarwin
  • 265
12
votes
6 answers

Windows Server 2008 without telnet client - how to test connecting to remote ports without installing anything new?

I'm looking to see if anyone knows of slick tricks to test connections to remote server ports from Windows server 2008 and variants that don't include the telnet client installed by default. Reason being, I sometimes have clients that want to…
S. Cobbs
  • 267
12
votes
3 answers

"-bash: telnet: command not found " error?

I have the following services running: sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off syslog 0:off 1:off 2:on 3:on 4:on 5:on 6:off tcsd 0:off 1:off 2:off 3:off 4:off 5:off …
Wei
  • 125
1
2 3
…
22 23