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.
336
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Connection closed by foreing host - Postifx, Dovecot
2024-02-07T10:44:27.271322+00:00 ubuntuserver postfix/postfix-script[23192]: starting the Postfix mail system
2024-02-07T10:44:27.277625+00:00 ubuntuserver postfix/master[23194]: daemon started -- ...
-1
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1
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31
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Telnet SmarterMail: 550 This is a submission only port. You must authenticate before sending mail
I have a "newer" server running Windows Server 2019 and I installed Smartermail FREE Edition so I could send mail via PHP/CDONTs from contact forms to my email address.
I tried matching the ...
0
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1
answer
5k
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EXIM SMTP allows to send mails without login / authentication via telnet to any domain
I'm ashamed, but I have to ask for help. My server is being used for sending spam, I've found out I can simply connect with telnet (edit: from any server in office, home and even directly from CMD/...
7
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3
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14k
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Send test mail using telnet via smtps (465) port
Based on this guide I am trying to send a test email using telnet from linux
https://linuxconfig.org/send-an-email-using-telnet
but the connection immediately disconnects:
$ telnet smtp.gmail.com 465
...
0
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1
answer
250
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connection refused mysql with telnet
i have 2 machines that can see each other and ping my issue is i want to telnet from slave machine to master machine and this is what i get:
slave@slave:~$ telnet 192.168.1.131 3306
Trying 192.168.1....
11
votes
3
answers
8k
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How to quit QEMU monitor?
I launched KVM VM with this command:
kvm /kvm/hdd/v1/v1-1.raw -m 512 -daemonize -smp 2 -nographic -net nic,model=virtio,macaddr=aa:aa:aa:aa:aa:01 -net tap,ifname=tap0 -monitor telnet:localhost:7001,...
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1
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73
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Can't telnet Apache2 Web Server from WAN on port 80
Is there specific port configuration to httpd.conf that opens port 80 aside from using Listen 80 directive?
netstat -aon gives LISTENING but I cannot telnet machineName 80 (says failed to connect)
PS: ...
0
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0
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90
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RHEL Server Accepts Telnet from all Clients Except a Rocky Linux VM
I have a few VMs on a XenServer. One is a RHEL 8.7 running SSH server. Another is a Rocky Linux 8 client and also some other Ubuntu and Windows systems. The Ubuntu and Windows systems can telnet to ...
0
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1
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115
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How to exit from telnet in xterm (ctrl+], ctrl+'+', ctrl+d) don't work
Can't exit from telnet while connected to host.
Commands like (Ctrl+], Ctrl+'+', Ctrl+D) etc. don't work.
I have tried all the suggestions from keyboard shortcut to quit 'telnet'.
Are there ...
1
vote
0
answers
228
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Not receiving any response from SMTP server after successfully connected via openssl or telnet
I am trying to set up my postfix using Gmail smtp relay server. I have set it up in other servers without issues, but I am having difficulty getting it to work in my work network.
I tested if there is ...
0
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0
answers
77
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How do I read telnet data and save to a new log file every day?
I use to use Indigo Terminal Emulator from shadeBlue. I can't buy a license anymore, shadeBlue is not in business, and I had to migrate servers. I am using Putty to read my data and save it to a log ...
0
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1
answer
60
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What is the name of the string that a service returns when you establish a tcp connection via telnet?
If you telnet to an ssh server, it will establish a connection and return a string, something like SSH-2.0-OpenSSH.... etc.
Something similar happens if you connect to a mysql server.
What exactly is ...
305
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8
answers
1.4m
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Check if port is open or closed on a Linux server?
How can I check if a port is listening on a Linux server?
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2
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6k
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Telnet: Unable to connect to remote host: Connection refused (Postfix - Ubuntu 14.04 VPS)
I have installed postfix following this tutorial but when I try to telnet mail.mydomain.com 110 (995,993,143 or 25) it throws the following error: Telnet: Unable to connect to remote host: Connection ...
50
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6
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128k
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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 ...
0
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2
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2k
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Sending Email by SMTP IIS7.5 via php site
After my company decided to change the website we switched from old ASP.NET site to new website created in Drupal(php). The site is running locally on IIS7.5 and we also have virtual SMTP server on ...
0
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1
answer
2k
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Missing or skipped ICMP_Seq In AIX Ping
I noticed an intermittent slow response on the ping from my application server to my database server. So to diagnose, I tested using a standard ping and Telnet tests.
For the telnet tests, it was ...
20
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3
answers
8k
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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?
1
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2
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3k
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"Connection failed" error when trying to telnet into SQL Server
I have an SQL Server running on a computer, and I'm trying to access it from another computer in the same local network (potentially VPN, since it's located in a datacenter). The point is that I can't ...
0
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0
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301
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Cisco Switch - Enable Telnet using HTTP
I'm trying to automate the configuration process of a Cisco switch (SG-300).
I was able to automate everything I need using telnet, but the last issue I still have is to enable telnet itself.
For now ...
0
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1
answer
571
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Automate time and date through telnet
im not very clued up with telnet commands but i am looking to automate logins for a device we use in the field. we are having issues with Cmos batteries and every time the power goes out (6 times a ...
1
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0
answers
544
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Linux: telnet arrives to target but no response
We have server in AWS that's trying to connect over TCP to an application in an on premise server but fails.
Initially we thought it might be routing/firewall issues so we tried to connect to that ...
0
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1
answer
2k
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How to telnet to a unix socket in debian to test memcached
To test memcached on Ubuntu, I would run this command:
echo "stats settings" | nc -U /run/mydir/memcached.sock
However now I have changed to Debian, and Debian nc does not support the -U ...
0
votes
1
answer
247
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Iptables + telnet not blocking ports
I have a Debian server from which I want to block all incoming and outgoing ports (especially all outgoing email ports), except those that I specifically add in iptables. The current setup I have is ...
0
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0
answers
427
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Telnet reconnect or maintain session?
We currently have several RFID Scanners connected to the backend via a telnet client.
However due to coverage of our wifi these scanners might lose there connection for a small period of time.
The ...
0
votes
1
answer
289
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telnet only works one way
I recently cloned two AWS CentOS 7 instances from a physical server. From the first AWS instance, I can telnet on port 22 to the second AWS instance. From the second AWS instance, I cannot telnet to ...
0
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0
answers
351
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Allowing IP & Port specific traffic for card terminal
I hope you can help me :)
I am setting up a credit card terminal in my store network. (It‘s just a mobile LTE Router with a static IP address and a switch)
The payment processing provider requires me ...
2
votes
1
answer
298
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All Outbound Traffic Uses IPV6
I have a Debian 10 server which has postfix installed, each time I try to send outbound mail traffic, the server uses IPV6 over IPV4. This causes postfix to log Connection timed out.
I have tried ...
1
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0
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690
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Postfix + Dovecot and folder "sent mail"
We’re using for sending mails our own mail server Postfix + Dovecot with parameter for Postfix sender_bcc_maps which ensures that sent mail thanks to blind copy (BCC) is also sent to a sender’s ...
0
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1
answer
5k
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Connecting To 127.0.0.1…Could not open connection to the host, on port 8123: Connect failed
Well aware this has been asked, but I have scoured Google/StackOverflow and tried every single suggested solution, without being able to connect to port 8123 on my local (which is running Windows 10). ...
12
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3
answers
149k
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"-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:...
0
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1
answer
3k
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How to use curl and telnet instead of cgi-fcgi?
I am using this script.c:
#include <fcgi_stdio.h>
#include <stdlib.h>
int main (void) {
while (FCGI_Accept() >= 0) {
printf("Status: 200 OK\r\n");
printf("Content-...
13
votes
3
answers
68k
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Contacting DNS server via command line interface [closed]
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 ...
0
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1
answer
619
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Telnet connects to server but cannot transmit data
Our client has a server and our web apps run on port 443 and 2000. Our client has two groups of IP addresses. One group is for the computers used in the company building. These computers can browse ...
0
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1
answer
252
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Simple code running in systemd exits to fast?
I had this old code base running in xinet d. It was basically a simple python script that waited for standard in to come in on a socket, it would do something with it and respond on standard out. ...
1
vote
1
answer
4k
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Windows to Linux Ping not working while Telnet works
On Linux we have a service running which is listening on port 9999 but when we try to check it from a Windows machine on same network with PING it says :
Ping request could not find host 10.32.9.82:...
2
votes
2
answers
2k
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Postfix - How to enable SMTP authentication on local delivery
I have an email server running Postfix. Everything is working fine,
However, recently, some internal emails received emails from their own addresses with phishing content.
After finding out, I learned ...
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3
answers
2k
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How does one make a temporary telnet responder with PowerShell? [closed]
I'm looking into making a temporary Telnet server so I can remotely test network connectivity and data transmission integrity. I don't have the authority to install the telnet server Windows Feature.
0
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1
answer
309
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How can I lock down an SSH and/or telnet user to only run a custom shell and no other commands or programs?
I asked this question on stack overflow, but I thought it might be more appropriate here on serverfault, because it has to do with system administration and security.
I am looking to prototype a ...
0
votes
1
answer
602
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telnet disabled, server 2012r2 still listening on port 23
How else can I disable telnet to comply with a security audit? The Telnet services roles are not enabled on this server. But it is LISTENING at 0.0.0.0:23. Also there is no local windows firewall to ...
0
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0
answers
305
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Azure VM, unable to connect from internet on ports configured (9089-9095)
I have created a VM on Azure with below steps:-
Created VM
Assigned a public static IP
Created a new Virtual Network (Subnet default - (10.0.0.0/24)
Did not create a NSG initially (NIC NSG was NONE - ...
0
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0
answers
579
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Host is not resolved but connecting via telnet, can somebody explain how?
In aws ec2 instance, rds host name is not resolved by ping or nslookup but it is still able to reach via telnet or nc how ?
~# nslookup xxxx.rds.amazonaws.com
nslookup: can't resolve '(null)': Name ...
1
vote
1
answer
1k
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How to connect to mail.hotmail.com via port 25 from DNS as instructed by Outlook
If you read https://sendersupport.olc.protection.outlook.com/pm/troubleshooting.aspx, it says
Confirm that your DNS is set up correctly
Try connecting to mail.hotmail.com via port 25. If you are ...
0
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1
answer
155
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Is there a "server" version of telnet? [closed]
If I want to quickly connect to a socket as a client and type something I can use telnet.
Is there a version of telnet or a similar program that provides the server-side of this?
In other words, is ...
2
votes
1
answer
5k
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How can I disable sending mail through postfix smtp without auth
I just setup a mail server with postfix 2.6.6 and dovecot.
I have the auth related config in main.cf like below:
smtpd_tls_cert_file=/etc/httpd/ssl/mail.crt
smtpd_tls_key_file=/etc/httpd/ssl/mail....
3
votes
3
answers
4k
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telnet non interactive: connection closed by foreign host
if I do
telnet host_ip port < /dev/null
Trying host_ip...
Connected to host_ip.
Escape character is '^]'.
Connection closed by foreign host.
By checking the wireshark, the client side sends tcp ...
0
votes
1
answer
203
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how to build a telnet middleware server
I need to comunicate an old crm system with a new asset.
Crm system can only send fixed commans over telnet connection but this new asset can only receibe commands via api rest.
Im planning to ...
1
vote
1
answer
145
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Service sometimes working, sometimes not working
I want to connect Centos B's 33060 port from Centos A.
I can ping Server B.
[root@serverb ~]# ping 10.42.40.182
PING 10.42.40.182 (10.42.40.182) 56(84) bytes of data.
64 bytes from 10.42.40.182: ...
4
votes
4
answers
17k
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How to forward UDP Wake-on-Lan port to broadcast IP with IPTABLES?
I'm trying to setup Wake-on-Lan for some of the LAN computers at home and it seems that I need to open a UDP port (7 or 9 being the most common) and forward all requests to the broadcast IP, which in ...
0
votes
1
answer
6k
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Execute command on LINUX via PUTTY from Windows [duplicate]
I want to open a putty session (SSH) from command line and immediately execute on the remote machine a specific command.
Something like:
putty.exe -ssh user@host -pw pass123 < "cd /some/...