Telnet is a protocol for bidirectional interactive text-oriented communication with remote hosts via virtual terminals. It is defined in [RFC 854](http://tools.ietf.org/html/rfc854). Telnet provides no inherent security and so is becoming less commonly supported. On modern UNIX-like systems it ...

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1answer
18 views

Postfix 2.11.3 Mail gateway: Recipient address rejected: User unknown in local recipient table

I am trying to recreate a mail-gateway for spam/antivirus-checks on a new debian system (Postfix 2.11.3) coming from an older OpenSuse Installation (Postfix 2.6.5). I tried to test it with "telnet ...
1
vote
1answer
14 views

Postfix/Amavis 451 4.3.0 : Temporary lookup failure

I am trying to set up a postfix server to prevent spam/malware. The server should reject incoming mail, that is suspicious, otherwise send it on to the actual mailservers which are listed in ...
4
votes
8answers
10k views

How to start a Windows GUI app from telnet

I have a GUI application running on a windows XP client machine. I would like to telnet in, shut it down, pull some files over via ftp and then start it up again. It's that last part that I'm having ...
-2
votes
1answer
23 views

Can't telnet to memcache server

I'm trying to connect the application server to the memcache server. App Server 12.12.12.12 Memcache Server 13.13.13.13 Memcache Port 11211 I've tried the following. Ping from 12.12.12.12 to 13....
2
votes
4answers
6k views

new Catalyst 2950 switch, no console or telnet CLI access

I am connecting a brand-new Catalyst 2950 switch to my LAN. It is on with green lights, and frames successfully go in and out the ports. The switch is on the same LAN has my host PC, and pings are ...
0
votes
0answers
36 views

Difference in telnet of amazon ec2 instance using internal and public IP

I have a 4 node hadoop cluster on ec2. We have configured Hortonworks Hadoop (HDP version 2.4) through Ambari. I have opened all traffic for our all four instances internally and the office external ...
0
votes
2answers
38 views

Iptables seems to be blocking outgoing HTTP connections

We recently noticed that outgoing HTTP traffic seems be blocked. Specifically we need to allow HTTP requests to a give website URL. I'm not sure if this is possible as I believe typically it must be ...
0
votes
1answer
42 views

Windows Server 2012 Telnet connection lost port 25

I am new to Windows servers, I have Windows Server 2012 and I am trying to set up and enable mail server (SMTP). I have followed this tutorial to instal and enable SMTP server and completed it ...
-4
votes
1answer
59 views

Try to Test Hack Attempt with Telnet [closed]

My server recently was attacked by hackers trying to run code on a web site, and I would like to test what they there trying to do. I'm not sure how to build the telnet command to do this. 2016-06-09 ...
1
vote
0answers
25 views

More Management VLANS for a switch

I created a management interface in vlan 99 to telnet the switch (2900 series). I also wanted to configure another management interface for the same switch from the computer belongs to the different ...
0
votes
0answers
57 views

“No route to host” when i do a telnet in azure

I have two VM's in azure with different public IP's and whose private IP's are : 10.10.1.9 10.10.1.6 When i do a telnet with following command from the server 10.10.1.6, i get the a error: telnet ...
-2
votes
1answer
50 views

Is it possible to access a Telnet server via SRV-Record?

I wanted to make a little telnet server using PHP as an addition to my website, which already looks like a terminal. I could create the telnet.example.com-subdomain, but that will take away the ...
0
votes
1answer
63 views

letsencrypt works www but not root domain (apache)

i'm trying to install letsencrypt on a server, both www and the root domains are hosted by the box. i can install with the www subdomain no problem, but not the root domain. here's the error i'm ...
1
vote
2answers
29 views

Telnet windows 2008 vs 2003

I have a mail server using powermta on a windows 2003 server (legacy). If I telnet into that server to test smtp connectivity, it works from other 2003 servers and from my dev machine running windows ...
0
votes
0answers
97 views

telnet “connection closed by foreign host” for some servers, not all

I started having issues connecting to our mail server on 1 server, but the others are able to connect without issue. telnet my.smtp.server 25 Trying 1.2.3.4... Connected to my.smtp.server. Escape ...
0
votes
1answer
45 views

Centos 7 network issue

I have a Centos 7 server behind a Dell sonicwall I have configured the sonicwall to allow certain services and this seems to work fine. However I can't telnet to some ports. I have added Wireshark to ...
8
votes
9answers
14k views

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 ...
0
votes
1answer
73 views

Firewall configured to allow 25/tcp but still cannot telnet into server on that port [duplicate]

I've got postfix and dovecot running on ports 25, 110, 587, 465, 993, 995 for the usual mail protocols. I can telnet into all ports except port 25 which you can see below. Any ideas on what's going on?...
58
votes
6answers
279k views

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

How can I check if a port is listening on a Linux server?
1
vote
1answer
48 views

Mailslurper connection timeout after 6 seconds

I'm trying to setup mailslurper for email testing but I keep getting a connection timeout after 6 seconds whether using telnet or netcat. I have left the config as default and mailserver creates the ...
0
votes
0answers
32 views

Implementing OpenVPN dynamic challenge/response

The OpenVPN docs for the management system (ref) say that dynamic challenge/response "works by returning a specially formatted error message after initial successful authentication." In theory, this ...
1
vote
0answers
47 views

Mail subdomain not connecting to Windows Server Virtual SMTP via Telnet Client

I trying to set up subdomain (e.g mail.mydomain.com) for use with a virtual SMTP server running on windows server 2012 SP2. I’ve tried to telnet with the command ‘telnet mail.mydomain.com 25’ but it ...
0
votes
1answer
1k views

Telnet to new SMTP server port 25 times out

I just got Postfix 2.9.6 up and running on a Debian 7 Wheezy server and I can send and receive mail to the outside world but I'm unable to login to the SMTP server. I've tried telnet, first by ...
0
votes
0answers
14 views

Setup router iptables like VPN for single pc

I'm currently far away from my office for a family visit. One of the applications got frozen and needs a restart. The config files are set up to only accept logins from local ips. Only device I ...
0
votes
0answers
132 views

Cannot telnet to port from Azure VM

I have an Azure VM setup and I have a program that SSH's out from that VM to port 7022 on my supplier's server. Sometimes I am unable to connect to this port and this can last for up to 30 minutes or ...
0
votes
0answers
11 views

Cannot connect to smtp mail server [duplicate]

I have an installation of Postfix & Dovecot on a Centos 7 server. While being logged into the server via ssh I am able to use telnet and openssl to connect to localhost like openssl s_client -...
0
votes
1answer
100 views

Telnet: Unable to connect to remote host

Related Threads: SMTP server works, but telnet to port 25 does not Can't connect to SMTP server The problem I have a server running Debian 3.2.65-1 and i am having some problems to connect other ...
1
vote
0answers
142 views

xinetd service is up but not listening on port 23

I am trying to open a telnet connection from a Wheezy VM to a router in GNS3 but even though the ping is successful, I am unable to open a telnet connection from the VM to any of the routers. the ...
0
votes
1answer
1k views

Azure VM ping and telnet not working

I have an azure VM (resource manager) on the new portal running windows server 2012 r2 with HPC with a public IP, Currently i can login to the VM using a remote desktop client but i cannot ping myself ...
-1
votes
3answers
739 views

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 ...
1
vote
1answer
162 views

Can't connect to python server on LAN

So I have this python server which just returns the uppercase sentence which came as a input: from socket import * serverPort = 12000 serverSocket = socket(AF_INET, SOCK_DGRAM) serverSocket.bind(('...
0
votes
3answers
2k views

Email server attack from telnet

My mail server having a problem on blocking some attacker that trying to telnet to our mailserver. but i'm not able to block it, ip will keep changing even we block by ip. seems like he is trying to ...
3
votes
3answers
9k views

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 ...
19
votes
5answers
38k views

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 ...
-1
votes
1answer
124 views

Telnet test pop3

I have problem with using POP3 to recieve e-mail from my VPS. In Mail app I'm getting message, that connection failed and I should check login and e-mail anyway, it's good. I try to check it via ...
0
votes
0answers
173 views

Windows Telnet Could Not Open Connection On Any Port, Connect Failed

Configuration: Host: Hyper-V Windows 2008 R2 Guest: Windows 2008 R2 No firewall, no antivirus Problem: After 5 or 6 days, the guest cannot make any TCP connection to outside, neither can do to ...
1
vote
0answers
240 views

Unable to access ReadyNAS 1100 via web admin portal and SSH [closed]

Device: ReadyNAS 1100 Model: RNR4000 Current firmware: RAIDiator 4.1.8 Latest firmware: RAIDiator 4.1.14 Purchased: December 2011 (3.9 years old) I am unable to access my ReadyNAS 1100 via the admin ...
1
vote
0answers
39 views

Allow console access to physical machines through telnet

We have a Super Micro server blade in our lab running a custom OS.The console of the OS can be accessed using the Super Micro web interface. A window gets created by running a .jnlp which needs to be ...
6
votes
2answers
32k views

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 ...
3
votes
1answer
299 views

Can I use HAProxy to load balance telnet connections?

We use HAProxy as load balancer for regular HTTP requests. I see no reference to telnet connections in the HAProxy configuration guide: HAProxy config guide. I was hoping to reuse HAProxy (or spin up ...
2
votes
2answers
16k views

Unable to connect to remote host: Connection timed out when trying to telnet to MySQL?

When trying to connect to mysql server via telnet I am getting following error: telnet localhost 3306 Trying ::1... Trying 127.0.0.1... telnet: Unable to connect to remote host: Connection timed out ...
0
votes
3answers
178 views

IMAP Port 143 Not Functioning When Using Hostname?

I am setting up a Mail Server on Azure (Windows Virtual Machine) using HMail and its all working great apart from not being able to connect my Outlook on my home PC. I believe the issue is that when ...
-1
votes
1answer
24 views

Sending commands to a set of session [closed]

In SecureCRT there is an option to send one command to all opened sessions (mainly for telnet/ssh connections). Does somebody familiar with some free program which can run on Windows that can do the ...
1
vote
0answers
103 views

Issue with executing net use command through telnet session

When executing net use command for mapping cifs share to windows drive. The drive is available only for that telnet session. But when i am doing it manually the drive is available permanent. ...
3
votes
1answer
2k views

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

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", ...
0
votes
0answers
203 views

Solaris 5.10 telnet connection closed by foreign host

I try to connect to a Solaris 5.10 server using telnet, but I only see: $ telnet xxx.xxx.xxx.xxx Trying xxx.xxx.xxx.xxx... Connected to xxx.xxx.xxx.xxx. Escape character is '^]'. Connection closed by ...
0
votes
1answer
717 views

Telnet: Unable to connect to remove 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 remove host: Connection ...
1
vote
1answer
196 views

Windows Server Port forwarding SSH to Telnet for multiple users

I have multiple installations with a specialized database framework (Intersystems Caché) that contains its own Telnet server running on port 23. Although the product does run on Windows Server 2008, ...
0
votes
2answers
1k views

Connections to host are sporadically successful with mysql_connect() and telnet, but I can always ping the host successfully?

When I try to connect to a host on my LAN with mysql_connect();, the connections succeed some of the time and fail at other times. I can always ping the MySQL server successfully, but when I try to ...
1
vote
1answer
167 views

OpenVZ - SMTP - telnet - Connection timed out

I have problem with SMTP in my OpenVZ container. I've created OpenVZ container by Proxmox on dedicated server in OVH. This container will be as mail server. So I create on "mother-server" rules to ...