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11

It's for convenience, but it's also a lower-than-user-level diagnostic. You can isolate the problem you're having with a service that way, for example: Joe has a database server and client. They are not communicating. Is the problem on the network? The server? The client? Joe goes to the client machine and opens a shell. He uses telnet, just as you ...


8

Check the file /etc/ttys which contains list of terminals. Only those marked "secure" will allow root to login. By default this is the console and all virtual terminals. Pseudo terminals do not allow root login. Also, in this day and age, where security is a big concern, may I ask why you are still using an unsecure protocol like telnet and not ssh ? ...


7

Telnet is a very simple protocol, where everything that you type in your client (with few exceptions) go to the wire, and everything that comes from the wire is shown in your terminal. The exception is the 0xFF byte, that setups some special communication states. As long as your communication doesn't contain this byte, you can use telnet as sort of a raw ...


7

Create a user and set his login shell to your command. For example: sudo apt-get install sl sudo adduser foo sudo chsh -s $(which sl) foo ssh foo@localhost Also have a look at man sshd_config for some other ways to configure you ssh server. (Like adding a ForceCommand.)


5

A more general solution than Laurentiu Roescu's would be to use iptables, which works the same in every distribution and essentially regardless of which software is installed. # iptables -A INPUT -p tcp -s <ip_address> --dport telnet -j DROP You may optionally use -j REJECT instead of -j DROP. Using REJECT will tell whoever is at the other end that ...


4

So here are in one answer a summary of my comments. You have 3 solutions depending on your environment: A. Your Windows host is connected to a network 1- Use "Bridge networking" And select the Windows network interface that is configured under Windows to have network access. Make sure you have no firewall on Ubuntu: sudo iptables -L should give you no ...


4

Instead of manually specifying the fingerprint (which can change), you can instead tell offlineimap where your local system certificates are stored and then have it automatically verify the chain. [Repository somerepos-remote] type = Gmail sslcacertfile = /etc/ssl/certs/ca-certificates.crt The sslcacertfile is what does the trick. If non-Ubuntu users ...


3

socat(1) could be of some help. From http://stuff.mit.edu/afs/sipb/machine/penguin-lust/src/socat-1.7.1.2/EXAMPLES: // poor mans 'telnetd' replacement # socat tcp-l:2023,reuseaddr,fork exec:/bin/login,pty,setsid,setpgid,stderr,ctty // and here an appropriate client: $ socat -,raw,echo=0 tcp:172.16.181.130:2023 Here, the example uses "login" which ...


3

On the first question, maybe the service does not wait for interactive input. There could be other explanations, too. On the second, nmap can be used to test the firewall. There are many options. Scan the first 1,000 ports (default): nmap -v -A -PN hostname.domainname.com Or perhaps a specific range: nmap -v -A -p 10000-11000 -PN ...


3

Why exactly can you connect via telnet to smtp port for example? Because both smtp and telnet protocols are implemented as plain-text. So with a telnet client, you can basically go connect to any port with a specific protocol that implements plain-text and you know how to communicate using the protocol.


3

You could do what the browser does, i.e. connect to the proxy, $ telnet proxy-server 3128 and talk to it. If there was no authentication, a simple GET request (followed by two newlines (Enter)) with a full hostname and protocol, e.g. GET http://www.google.com/ HTTP/1.1 should suffice. Since you need authentication, you need to provide your username ...


3

telnet reads from ~/.telnetrc at startup, but that won't help you with typing long hostnames. For that you should make yourself some shell functions like this: t1 () { telnet foo.bar.blat; } t2 () { telnet crock.fook.ack; } t3 () { ... and so on... } Put them in your .bashrc, or .zshrc or whatever your shell reads at startup and then type t1 when you ...


3

If you are asking "What is the way to connect to an SMTP server using SSH instead of telnet?" the answer is there is none. SSH only communicates over ports using the SSH protocol. Using it to connect to any other port will fail, because SSH will try to speak the SSH protocol, which will not be understood by an SMTP server (or FTP, or other server ...


3

Because there's nothing listening there. If you'd expect an X server to answer, you'll need to tell it to enable TCP (remove the -nolisten tcp for instance). But if you don't need your X server to be accessed directly over the network (other than tunnelled/proxied over ssh), it's probably wiser to leave it there. You can connect to your X server with a ...


2

I finally found an answer in Anne Baretta's Linux Keyboard Hall of Shame... it seems that changing key mappings in xterm / rxvt does no good for telnet. I validated this when I sniffed the telnet connection. First I sniffed the telnet session and saw that Backspace sent 0x7f to the host. Next I intentionally broke Backspace in rxvt using stty erase $ (thus ...


2

There is Jabber Telnet Bot that is bot that provides jabber to telnet gateway. Project is little old, and I was unable to run in successfully, but there is a chance that it will run on another configurations. After downloading package you need to modify configuration in cfg/jbtelbot.conf file to set host where you want to connect and Jabber account on which ...


2

I'm pretty sure this is problem with network configuration on you VirtualBox. Open up VM settings: Make sure you select Bridged Adapter ( I expect you have NAT configured which does not allows to route connections from outside to your VM) Select available network card (I used MS Loopback adapter, on your PC it will be different) More info here and ...


2

You can use Proxychains for this. First install proxychains, using the command: $ apt-get install proxychains Then configure your proxy settings in /etc/proxychains.conf file. Add at last, these lines for HTTP and HTTPS proxy. http proxy-ip proxy-port username password https proxy-ip proxy-port username password Now you ...


2

At risk of sounding daft, why not just use PuTTY? If you already like the functionality it gives you, just run it. PuTTY is available for Linux or Windows As already pointed out in comments, telnet isn't raw - it expects certain protocols to be followed.


2

Have you tried turning off localchars in your telnet client? bash$ telnet telnet> toggle localchars Won't recognize certain control characters. telnet> open myhost You may also be able to put this command in the ~/.telnetrc file, depending on your version of telnet.


2

You might try the 8-bit clean mode... it stops telnet from interpreting much of the data telnet -8 host port (This is a shot in the dark) For the most part, you're on the right track, trying to get telnet to stop pre-interpreting keystrokes... such as the CTRL-C and CTRL-Z and others. 8bit mode should help.


2

You might want to start with something a lot simpler to get started in this sort of thing, as it sounds as if you are new to it. Perhaps the old talk / talkd command line program and daemon would be more approachable? Some valuable resources include APUE, or Advanced Programming in the UNIX Environment (Stevens), UNP, or UNIX Network Programming (Also by ...


2

Because Telnet is designed to be an interactive tool to interact with a smart terminal. It doesn't receive the right terminal data (TERM environment variable etc) when fed from a pipe. Also, it performs negotiations with the remote host for terminal parameters, which may disturb the communications. The right tool for application like yours - non-interactive ...


1

Before going there, go read the specifications of the telnet protocol (RFC 854, see also the Wikipedia entry for the full list of RFCs involved). Telnet is a very complex protocol, as it was designed to connect between machines of a wild variety of operating systems, down to different character coding. Moreover, it is recommended to never use it, as it is ...


1

Is it a strict requirement, that you have to use telnet to accomplish the task? If not, please consider using an ssh connection to the server. ssh username@domain.com At command line after giving a password: cp /home/of/user/A/fileX /home/of/user/B These commands would do the trick in that case.


1

Each console has a process associated with it. You can usually find them on the process list easily enough. On Ubuntu it is called getty or agetty. On other systems it might be login, or it could just be a shell process. All you have to do is disable that process to shut down the serial port. You can't kill it because init will just spawn a fresh one, but ...


1

You can use telnet to connect to any port provided that there is something listening to that port and it is not blocked by a firewall. telnet alt1.aspmx.l.google.com 25 telnet google.com 80 Will all work fine. However, you must know what protocol is used by the other end of the connection otherwise, it is kind of pointless. Note that telnet sends ...


1

I'm on Debian at the moment, and I see both a client (package mactelnet-client) and server (predictably, mactelnet-server). In the case of the client, mactelnet is the binary to run. I'd be very wary of the security aspect in a piece of software like this, though. Linux TCP/IP has a well-established, peer-reviewed, often audited stack and toolset. However, ...


1

Programs are supposed to query the terminal settings to find out what the backspace character is (^h and ^?, i.e. \010 and \177, are the two choices out there). Use stty erase '^h' or stty erase '^?' to declare what your terminal sends. If you log in remotely (with telnet, rsh or ssh) inside the terminal, note that you must run stty on the application side. ...


1

Backspace and Control-H were designed to be the same thing but nowadays, especially on Linux, you often have backspace sending delete and delete sending some odd escape sequence. In any case and as far as I know, telnet or the TERM variable shouldn't change what backspace sends, this is usually a terminal emulator configuration feature.



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