Telnet Server On CentOS 7

Hi

I have users that log in to our linux server using telnet. Just yesterday out of the blue, the Telnet services would automatically stop, and so I have to log in through ssh to manually start the telnet services in order for users to log in.

Thanks in advance.

*I am a linux newbie, and have taken from a guy that left abruptly so Im still trying to teach myself cmds.

Good Morning! I am supporting the coffee and Doritos industry with my frustration with this problem. I have been battling it for two months. I have several Red Hat books, the official Red Hat study guide, and have searched the forums for weeks with no avail. I was wondering if you have ever had this?

I am trying to "telnet server.example.com 25" or telnet in general. Both servers are running on a KVM on the 192.168.122.0/24 network.


[root@server ~]# telnet server.example.com
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Trying 192.168.122.191...
telnet: connect to address 192.168.122.191: Connection refused

I can ssh, run NFS, and also run internal postfix e-mails.

IPTABLES IS TURNED OFF ON BOTH CLIENTS

Postfix and Telnet is configured on both clients, with both listening:

[root@server ~]# netstat -tulpn |grep :25
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1802/

When I Telnet from client named 'Server' to client named 'ISCSI', tpcdump on client 'ISCSI' gives the following:

19:01:23.579330 STP 802.1d, Config, Flags [none], bridge-id 8000.52:54:00:2e:85:0e.8003, length 43
19:01:23.632750 IP server.57477 > iscsi.example.com.telnet: Flags [S], seq 2403459934, win 14600, options [mss 1460,sackOK,TS val 2679191 ecr 0,nop,wscale 6], length 0
19:01:23.632882 IP iscsi.example.com.telnet > server.57477: Flags [R.], seq 0, ack 2403459935, win 0, length 0
19:01:24.428091 IP server.57478 > iscsi.example.com.telnet: Flags [S], seq 942066757, win 14600, options [mss 1460,sackOK,TS val 2679990 ecr 0,nop,wscale 6], length 0
19:01:24.428163 IP iscsi.example.com.telnet > server.57478: Flags [R.], seq 0, ack 942066758, win 0, length 0
19:01:25.006222 IP server.57479 > iscsi.example.com.telnet: Flags [S], seq 2689610466, win 14600, options [mss 1460,sackOK,TS val 2680564 ecr 0,nop,wscale 6], length 0

I am currently working on a sbc6000x board with linux 2.6.24 on it and would like to use the telnetd command from busybox (v1.4.2).
I can run the Telnet daemon on the board and try to connect to it from another computer but each time the connection close.

In the terminal of the computer i have : (i changed the ip with Ipoftheboard here)

Trying Ipoftheboard
Connected to Ipoftheboard
Escape character is '^]'.
Connection closed by foreign host.

I already tried to use the hosts.allow file with :
ALL : Ipofthecomputer

And i checked in /etc/initd.conf and Telnet is enabled.
I read that maybe the connection is closing because i don't have a user/password configured for the Telnet connection but i can't find where to configure them.

I must use Telnet, i can't use another solution like ssh.

I have a virtual machine on VmWare 10.0.1
Right now I am trying to make it a web server, apache works and machine has access to the Internet and i can even ping it from other pc from my network but can not connect to it by telnet.
Iptables is set to let everything inside and outside apache works.
PS Sorry for the stupid questions and bad english.

Hello,

I try to use a ftp daemon and a Telnet daemon with inetd and the BusyBox v1.19.0 on a linux 2.6.24.

When running inetd and then checking what is listening with "netstat -an |grep LISTEN" i have :
Code:

netstat: /proc/net/tcp6: No such file or directory
netstat: /proc/net/udp6: No such file or directory
netstat: /proc/net/raw6: No such file or directory
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN

tcp        0      0 0.0.0.0:21              0.0.0.0:*               LISTEN

tcp        0      0 0.0.0.0:23              0.0.0.0:*               LISTEN

ftp port 21 and Telnet port 23 seems to be listening.

My inetd.conf file is :

Code:

#<service_name>    <sock_type>    <proto>    <flags> <user>     <server_path>     <args> 

21 stream tcp nowait root ftpd ftpd /etc
telnet            stream        tcp        nowait    root    /usr/sbin/telnetd

I have no rule in my hosts.deny so nothing should be stopped and i have no iptables firewall in place too.

When typing "ftp://ipofthetarget" in a web browser i have a error :

Code:

504 Gateway Timeout
Gateway timeout expired while waiting for server response.

And when trying to Telnet from another computer or "Telnet localhost" from the board i have :
Code:

# telnet 10.2.29.201
Trying 10.2.29.201...
connected to 10.2.29.201.
Escape character is '^]'

Connection closed by foreign host.

This would mean that the connection for Telnet exist but why is it closing ?

Thank you for your future answers !

UPDATE 1 :
If i try to run telnetd like this :
/usb/sbin/telnet -l /bin/sh
i can connect anonymously from another computer, not perfect because i would like a user/password but still of use.
The problem with the ftp daemon still exist.

UPDATE 2 :
Trying from Windows cmd or linux terminal : ftp ipofthetarget seems to work
Not perfect because i would like a user/password too but still of use.

I am still open for suggestion for the user/password thing. I am not deleting the thread in case someone interested about this exist.

Hi All,
We have qmail server running on RHEL6.5. We have already made sure that our server is not acting as an open relay with the help of http://mxtoolbox.com/diagnostic.aspx.
But still anyone can telnet to our domain and send fake emails to anybody@ourdomain.com. For example Code:

telnet mail.ourdomain.com 25
helo mail.ourdomain.com
mail from: unknown@anyname.com
rcpt to: anyemailid@ourdomain.com
data
from: "Any Unknow name" <unknown@anyname.com>
to: "Some user Name" <anyemailid@ourdomain.com>
subject: Testing MTA with telnet

Hi,
This way anybody can fool us.

Regards,

.
quit

So can anybody pls help me to prevent this. I meant to say, we should not block port 25, instead it should verify whether or not "from email id" is exist in our domain, if it is exist then it should ask for the password also or if it is not exist then also it should not take us to next step. Because as per above example anybody can fool us as the mail is coming from outside but it is just from our domain to our domain without any authentication!!!
Expecting your kind help to block sending mails in this way.

Hi,

i am trying the run a ftp daemon on my board (sbc6000x) but it seems that the ftpd service is never started by inetd.conf.

My inetd.conf is :

Code:

#<service_name>	<sock_type>	<proto>	<flags> <user> 	<server_path> 	<args> 

ftp			stream		tcp		nowait	root	/usr/bin/ftpd ftpd -w
telnet			stream		tcp		nowait	root    /usr/sbin/telnetd

Telnet don't run too but this is because i am missing some folders and i can launch it manually after creating the folders without issue, but maybe the fact that it can't run telnet because of the missing folders make it stop trying the ftp daemon ?

I check with the command "ps", the processus is not running hidden anywhere.

Hi All,

I am trying to send email using telnet to smtp as mailx and other functionality is restricted by administrator.

I am not able to figure out as how to attach any text or any file using the below.

I am following all instructions and steps as shown at http://exchange.mvps.org/smtp_frames.htm

1. telnet <servername> 25
2. helo <your domain name><enter>
3. mail from: <your Email Address><enter>
response should be as follows
250 OK - mail from <your Email address>

rcpt to: <recipient address><enter>
response should be as follows
250 OK - Recipient <recipient address>

data<enter>
response should be as follows
354 Send data. End with CRLF.CRLF

To: <recipient's display name><enter>
From: <your display name><enter>
Subject: <Subject field of Email message><enter>
<Enter you body text><enter><enter> . <enter>
response should be as follows
250 OK

quit<enter>

HI friends,

I'm a new learner i want to know how to configure ssh and telnet services in linux.

I had used CentOS 6.6(desktop) before now install centos 7(desktop) on my pc.
In centOS 6.6 had “Connect to Server” in the Places menu, select “Public FTP” or “FTP (with login)” as the service type, enter the server name and other parameters (you can define bookmarks in this dialog box too),

But I cannot find it on centOS 7.I need to login Ftp via Connect to Server.