So sometimes I’m on a box and need to test if a port is cleared on a firewall.. i may not yet have apache installed but I want to test if port 80 is open, or I may want to act as a server to grab a request..
simple with Netcat.
nc -l -p 8080
will open a listen on port 8080 and after the first connect, exit and go back to shell… useful for testing
A common monitoring system, Nagios, uses qpage for sending alphanumeric pages via a modem.. yes it sound insane, but think about what happens to your monitoring system when your internet connection drops, unless your using outside monitoring, your not going to get that email to send you a page.
I ran into an issue with the modem not dialing quickly enough and had a few tips for getting it going.
1) Make sure that your calling the correct dialing group.
2) Check the modem in minicom, load it up, and do a few
AT[ENTER]
OK
ATZ[ENTER]
OK
to make sure the modem is reset, and then do a
ATDT 2125551212[ENTER]
{it should pause and dial the number [in this case, 212-555-1212] and either tell you BUSY, CONNECTED, or error out.
Just thought I’d toss out a few reminders.
I’ve had to look up this context enough that I figured I should put it out, TFTP is a fantastic way to keep your switches in order, and on our foundries it can become a huge issue when doing multiple setups (and their interface isn’t all that friendly)
To upload from the switch to the server, make sure TFTP is running on the server and create a file in the root directory, with permissions of 777 for world writing (or at least writable by the TFTP server). I do this on a controlled server.
SSH@yourfoundry.switch.com#copy running-config tftp IPofTFTPServer filename
SSH@yourfoundry.switch.com#Upload running-config to TFTP server done.
I then edit the file locally with VI, and then when I’m completed download it to the switch and restart.
To Download the file from the server to the switch’s startup-config:
SSH@yourfoundry.switch.com#copy tftp startup-config IPofTFTPServer filename