[SOLVED] 'construct' a packet?

qrange · 06-28-2011, 06:11 AM

we have a minor issue with time synchronization in proprietary equipment.
the client needs to synchronize time with server, but not using NTP.
it is not very important so doesn't need to be done often.

the problem is that it won't synchronize. I can see the server is sending tcp packet with date&time, but the client ignores it.
I suspect the problem is in format (manual specifies there are two possible options like MM: DD: YYYY and so on, but server seems to use some other)

Is there an easy way to run some program in Linux Debian, to send that simple packet with correct date?

(the IP address of server can be configured in client)

unSpawn · 06-28-2011, 05:34 PM

You could muck with a telnet server (bad), netcat, a web server CGI or use something that might be already there, is configurable, has builtin ACLs etc, etc like Xinetd. For example a simple service configuration like:

Code:

]$ cat /etc/xinetd.d/timetell
# default: on
# description: 
service timetell 
{
        disable = no
        socket_type     = stream
        protocol        = tcp
        port            = 9999
        type            = UNLISTED
        wait            = no
        user            = root
        server          = /bin/date
        server_args     = +%Y:%m:%d
        log_on_failure  += USERID
        only_from       = 127.0.0.1 192.168.0.0/16
}

...would return just "fullyear:month:day" plain text when polled on port TCP/9999.

qrange · 06-30-2011, 08:08 AM

thanks.
so, I need to install xinetd in debian, but it conflicts with inet-superserver (openbsd-inetd).

what to do?

edit: can it be done with inetd?

unSpawn · 06-30-2011, 02:16 PM

Sure, can't see why not.

qrange · 07-01-2011, 01:42 AM

er, could you tell me how to modify your example for inetd?
I'm somewhat clueless about it, never used it before in such way.
thanks.

edit: this has been solved, (the problem was indeed in format) I found the instructions on google and edited /etc/inetd.conf
works great