Wily_One Premium Member join:2002-11-24 San Jose, CA
1 recommendation |
to treich
Re: how do I disable people telneting into my mail serverFirst of all, if you are really telnetting into your system you should disable telnet altogether and use SSH.
As for port probing, which is what this is, you can't do much to prevent it. You can block repeat offenders with something like iptables. |
actions · 2013-Nov-15 4:35 pm · (locked) |
graysonf MVM join:1999-07-16 Fort Lauderdale, FL |
Telnet, in the context of this thread, refers to using a telnet client to connect to a TCP service port, not the insecure practice of telnetting to to a telnetd daemon for shell access. |
actions · 2013-Nov-15 5:04 pm · (locked) |
dave Premium Member join:2000-05-04 not in ohio |
to Wily_One
telnet clients can be used as a way to make a TCP connection to any TCP port, and then send bytes on that connection. In this sense, the telnet client is simply a handy program to copy bytes from keyboard to TCP connection.
Whether you can operate the protocol that the server is expecting depends on your own skill - e.g. whether you can type SMTP on-the-fly and generally without recourse to a delete key. |
actions · 2013-Nov-15 5:36 pm · (locked) |
graysonf MVM join:1999-07-16 Fort Lauderdale, FL |
LOL. Never tried the delete key Backspace doesn't work either |
actions · 2013-Nov-15 5:40 pm · (locked) |
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leibold MVM join:2002-07-09 Sunnyvale, CA Netgear CG3000DCR ZyXEL P-663HN-51
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Some telnet clients use line buffering which allows the backspace key to work as expected (since the correction takes place before the data is send to the server). It is amazing how frequently that backspace key is being used subconsciously. I can remember times when a quick telnet test didn't work as intended only to find a ^h or \008 in the server side log files |
actions · 2013-Nov-15 6:40 pm · (locked) |
graysonf MVM join:1999-07-16 Fort Lauderdale, FL |
Yes, a client I use once in a while has a type ahead box you can stuff the whole line in, and it all sits there capable of being corrected until the Enter key is pressed. But I rarely use it. For me it's easier to spawn the session in shell and live with the occasional mistake. |
actions · 2013-Nov-15 6:51 pm · (locked) |
Wily_One Premium Member join:2002-11-24 San Jose, CA |
to graysonf
Was there anything in my post that made it sound like I didn't know that? I telnet to specific ports all the time to verify the firewall is not blocking it.
User complaining about port probes. Then people go on a tangent about him knowing or not knowing how to telnet into his own server. That is the context for my comment about that not being a good idea. Use SSH for server access, not telnet.
Keep using telnet for server access - I don't give a shit. LOL |
actions · 2013-Nov-15 6:52 pm · (locked) |
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