Hot answers tagged telnet
42
It is a reasonable concern as there are tools that accomplish arp poisoning (spoofing) that allow you convince computers that you are the gateway. An example and relatively easy to use tool would be ettercap that automates the whole process. It will convince their computer that you are the gateway and sniff the traffic, it will also forward packets so ...
42
The usual tool for this is something called netcat. It's available in most Linux distros, and may even be installed by default in some (the command is nc). There are even ports for Windows, but nearly every antivirus package on the planet considers it deeply suspicious due it's use in malware which makes it hard to download and use.
21
Yes, but it's not just because of your use of Telnet and your weak passwords, it's because of your attitude towards security.
Good security comes in layers. You should not assume that because you have a good firewall, your internal security can be weak. You should assume that at some point in time, your firewall will be compromised, the workstations will ...
13
When you say, on the bash shell, I am assuming this shell is running on the computer at the locations you mention. If you have SSH to some other host and ran ftp/telnet then these answers are irrelevant.
can my coworker see it?
Maybe, if your are both connected to a hub, if you are on a switch and he hasn't done anything evil like arp poisoning he ...
11
You can install OpenSSL for Windows, and use it to connect to servers using SSL. Type this in the command line:
openssl s_client -connect pop.gmail.com:995
By the way, Gmail's SMTP servers require authentication too (unless you're connecting from anotehr known mail server), so you'd better start with something simpler.
11
Unless you really need telnet for some unusual reason, don't use telnet for this.
SSH can provide the same environment, but provides encryption and plenty of other useful features. Telnet on the other hand provides no security at all, passwords are sent in plain text. Certainly, I wouldn't even consider allowing telnet outside of a home lan or other secure ...
10
1) on host a: telnet listen 12345
$ ls | nc -l -p 12345
Depends on the distro and netcat version, you may not need -p option.
2) on host b: telnet host_a 12345
$ telnet host_a 12345
1159.rar
12030.mp4
123.mp4
124.mp4
129
129.bak
...
9
Telnet provides the ability to communicate with a service, nothing more nothing less. If that service happens to be a shell on a server, great, but it's not always. I often use telnet to send a malformed HTTP request manually, or to manually run commands against an SMTP server.
SSH is way more than just a way of logging on to a server remotely. It can be ...
8
You can use pam_succeed_if in your /etc/pam.d/telnet or similar file:
auth required pam_suceed_if.so user = ${telnet_user} quiet
Where ${telnet_user} is the user allowed to use telnet.
But, if you weren't aware, telnet is a Bad Thing. The allowed account's details can easily be sniffed and may enable other people to use the account. Really do you SSH if ...
8
Ick. You're going to have to base64 encode the attachment and create the MIME headers.
Rather than generating a new message "on the fly" each time, it would probably be easier just to email yourself a very short example message from a "real" email program (leveraging the work that the people who wrote it did to put the attachment into the proper encoding ...
7
It looks like this is not possible with the Windows telnet service. I even tested running the service under the local system account with "interact with desktop" enabled, but that did not work (which is fine as it would have serious security implications).
As an alternative to using telnet, I would recommend PsExec. PsExec is part of the SysInternal tools ...
7
Anyone with the ability to sniff the traffic between you and the site that you have connected to can potentially read your ftp password, or any data that travels unencrypted.
So, realistically, all scenarios above will be possible, with the following notes:
1) Your co-worker would either have to be able to tap into your external network, or be able to ...
7
Are you using Windows or Linux (*NIX)? The good old BBS type of file transfers work perfectly under telnet. You need to get the programs thought, and compile them. See zmodem and xmodem.
7
You've got a small learning curve ahead of you:
A command line / command prompt is simply one way that programs present themselves to the user; via a CLI (command line interface). The other way is through a GUI (graphical user interface). Many programs have both kinds: you can choose which to use, graphical or command-line. It's a matter of taste. An ...
7
The software listening on port 11211 doesn't support IPv6. Since localhost is an entry in the hosts file that tries an IPv6 address first, you only fail back to IPv4 after IPv6 fails. You can solve the issue by either getting the software updated (or properly configured to listen on IPv6 if it's an option in the config file) or changing your command to ...
6
Port 25 is not the telnet port. It is the SMTP port, and what you're getting is the response from the SMTP server — as you say, "still the SMTP listens".
When you are using the telnet client this way, you are not actually using the telnet protocol. You're using the same command, but conveniently, unless you connect to something that starts sending the ...
6
If you are not expecting to receive email via SMTP, then you can either (a) block port 25 on your firewall, or (b) configure your MTA so that it is not listening for incoming connections on port 25. The latter choice is in many ways a better solution, but exactly how you accomplish that depends on your MTA. It looks like you're running Postfix, so this ...
6
When connected to the monitor via telnet, anything that you type will be interpreted as a command by the monitor itself. You can view the full list of commands in the QEMU Emulator User Documentation, one of which is quit (or q for short).
To disconnect the telnet session you need to first use the telnet escape key which is Ctrl-] and then you can type quit ...
6
While hand testing SMTP servers by hand is possible and viable, using a tool designed for this will be much easier.
This article explains SWAKS. swaks is designed for smtp server testing. Supports attachments, authentication and encryption!
6
Ages ago I wrote a COM server to allow me to do telnet from VBScript. If you want a copy (including source) I'd be happy to put it on the Internet somewhere. I use it for remotely rebooting routers.
To give you some idea of what it does, here's an example script (with error checking removed)
const SVR = "www.microsoft.com"
dim telnet, s, i
set telnet = ...
6
The right answer is somewhere between the size of the install-base of FTP and Telnet, and the relative complexity of SSH/SFTP. Every SSH client I'm aware of gives a big scary warning like:
The authenticity of host 'example.com (10.0.0.1)' can't be established.
RSA key fingerprint is 17:cf:fb:1c:82:19:39:12:b1:76:a6:a1:8a:ff:34:75.
Are you sure you want to ...
6
You could add a static route to the host you are connecting to.
For example...
You connect to 10.10.6.5
Interface 1: 192.168.1.50/32
Interface 2: 192.168.2.50/32
Default gateway: 192.168.1.1
Static route for 192.168.2.0/24 to 192.168.2.1
If you want to connect to 10.10.6.5 via 192.168.2.1, you add this static route:
route add 10.10.6.5 mask ...
5
I think you may want to look into a service that can provide you with a dns domain name for your home computer. The following is one I have used with great success over the years: DynDNS.com
Basically, they use a service that runs on your computer that will update the dns record whenever the IP address of your home computer/router changes.
5
You can do it with netcat, but it's a huge security hole:
http://www.stearns.org/nc/
http://forums.remote-exploit.org/newbie-area/5857-netcat-port-redirection.html
mknod backpipe p
nc -l -p 80 0<backpipe | tee -a inflow | nc localhost 81 | tee -a outflow 1>backpipe
FWIW, this is probably a profoundly bad idea.... make sure your firewall is tight ...
5
Your first example is telling ssh to connect to the ssh daemon (server side process) on a non-standard port, in this case, 25. If the sshd daemon is not listening on this port, the connection attempt will time out or error with a protocol problem, as you're experiencing.
The second is telling ssh to make a normal connection to "serveraccount" (which ...
5
Okay, so using everyone's comments as a starting point I came up with this silly mess :-) ...
{
sleep 5;
echo 'ehlo';
sleep 3;
echo 'MAIL FROM:<Test@test.com>';
sleep 3;
echo 'RCPT TO: <kyle@test_dest.com>';
sleep 3;
echo 'DATA';
sleep 3;
echo -e 'To:kyle@testdest.com\nMIME-Version: 1.0 (mime-construct ...
5
You can telnet to another machine using its name, but the name should be resolvable.
If it is defined in your hosts file, the found IP mapping will be used.
If it is resolvable via DNS server, it should be OK also.
If it is a netbios name (it appears so), you need to have winbind package installed (I am assuming Linux OS here). Under Windows, resolving ...
5
Assuming your problem does occur while doing telnet localhost 25 your session has to look like this:
(...)
DATA
354 End data with <CR><LF>.<CR><LF>
Subject: Test ...
5
Your syntex needs to start with helo dominaname.com. Example below. Make sure to use enter spaces correct and the period at the end.
telnet xxx.domainname.com 25
helo domainname.com
mail from: myaddress@domain.com
rcpt to:youraddress@domain.com
data
to: myaddress@domain.com
from: myaddress@domain.com
Subject:This is a ...
4
You could use a browser and go to http://mailserver.tld:25
Naturally you won't get a web page back, but IE for example has a different error page for 'failed to download page' vs 'can't connect to server' which is how you would decide if connectivity was established or not.
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