This depends in part on your operating system. There is however no limit on a specific port. There is a limit on the number of concurrent connections however, typically limited by the number of file descriptors the kernel supports (eg 2048). The thing to remember is that a TCP connection is unique and a connection … Read more
My bad. The problem was with the curly braces. They are supposed to be at the same line as the expect command .
Have to recomment the Exploring Expect book for all expect programmers — invaluable. I’ve rewritten your code: (untested) proc login {user pass} { expect “login:” send “$user\r” expect “password:” send “$pass\r” } set username spongebob set passwords {squarepants rhombuspants} set index 0 spawn telnet 192.168.40.100 login $username [lindex $passwords $index] expect { “login incorrect” { … Read more
I’ve used various methods for scripting telnet sessions under Unix, but the simplest one is probably a sequence of echo and sleep commands, with their output piped into telnet. Piping the output into another command is also a possibility. Silly example (echo password; echo “show ip route”; sleep 1; echo “quit” ) | telnet myrouter … Read more
Found a way, thanks to the link here (with the original google group discussion here) First, Telnet to your server: telnet 127.0.0.1 11211 Next, list the items to get the slab ids: stats items STAT items:3:number 1 STAT items:3:age 498 STAT items:22:number 1 STAT items:22:age 498 END The first number after ‘items’ is the slab … Read more
In Windows, an executable is either a console application or a Windows application (or a SFU or Native application, but that doesn’t matter here). The kernel checks a flag in the executable to determine which. When starting using CreateProcess WinAPI function, if it is a console application, the kernel will create a console window for … Read more
Interesting. I had more luck sending IAC WILL ECHO IAC WILL SUPPRESS_GO_AHEAD IAC WONT LINEMODE 255 251 1 255 251 3 255 252 34 The IAC WONT LINEMODE seems to be redundant: my telnet client seems to get to the right state without it, but I left it in for completeness.
While I’d suggest using expect, too, for non-interactive use the normal shell commands might suffice. telnet accepts its command on stdin, so you just need to pipe or write the commands into it through heredoc: telnet 10.1.1.1 <<EOF remotecommand 1 remotecommand 2 EOF (Edit: Judging from the comments, the remote command needs some time to … Read more
The ‘\r’ character is the carriage return, and the carriage return-newline pair is both needed for newline in a network virtual terminal session. From the old telnet specification (RFC 854) (page 11): The sequence “CR LF”, as defined, will cause the NVT to be positioned at the left margin of the next print line (as … Read more
As pointed by B. Rhodes, nc (netcat) will do the job. A more compact way to use it: nc -z <host> <port> That way nc will only check if the port is open, exiting with 0 on success, 1 on failure. For a quick interactive check (with a 5 seconds timeout): nc -z -v -w5 … Read more