(I know this is mostly-Linux unrelated, but some people here
who use Alcatel moedm as a router, with Linux, can find it useful)
While doing a routine telnet to my modem, I've discovered that
you can get a remarkable amount of information regarding the
activity of your modem, on the fly.
This is important especially for those of us who need to
update their dynamic IP on a dynamic DNS host server
every time it is changed.
I've proviously written a script that pulls the IP from the
modem by running telnet, and let it run every 5 minutes (BTW,
I also solved the problem with identd). But now, after discovering
the logging information, I can write a daemon that waits for the
modem to report the IP change.
The logging is activated by connecting using TCP/IP to
the modem (usually 10.0.0.138), and sending the 0x11 byte:
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
int main()
{
int sock, rc;
struct sockaddr_in sin = {0,};
char buf;
sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == -1) {
perror("sock");
return -1;
}
sin.sin_family = AF_INET;
sin.sin_port = htons(23);
sin.sin_addr.s_addr = inet_addr("10.0.0.138");
rc = connect(sock, (struct sockaddr *)&sin, sizeof(sin));
if (rc != 0) {
perror("connect");
return -1;
}
sleep(1);
recv(sock, buf, sizeof(buf), 0);
buf = 0x11;
send(sock, &buf, 1, 0);
dup2(sock, 0);
execl("/bin/cat", "/bin/cat", NULL);
return 0;
}
Running this while connecting to my ISP, I get on my side:
-----------------------------------------------------------------------
Bit Swap Report (for line 0)
CarrierNr Bi Old Bi New GiOld GiNew
========= ====== ====== ===== =====
38 2 0 -14.5 -12.5
57 2 3 -14.5 -14.5
Results of bitswap algorithm :
==============================
Minimum noise margin : 17.1 dB (on carrier 56)
Maximum noise margin : 25.8 dB (on carrier 78)
Total gain power : 10.4
Nominal Gi : -12.0 dB
Boost Gi : -12.0 dB
-----------------------------------------------------------------------
RX BITSWAP REQUEST ...
PILOT_ERASE ON
PILOT_ERASE OFF
done at sync 7 and symb 0
[0] E - : PPP_SET_ROUTE
<enter attach atm 0
[0] E - : PPP_LINK_OPEN
[0] E - : PPP_LINK_UP
[0] E - : Link Started
[0] E - : PPP_SET_DETCB
[Remote message: Welcome to NetVision, hana aloni
]
[0] E - : local IP address 199.203.153.213
[0] E - : remote IP address 199.203.153.1
Unfortunately this doesn't slove the problem of what if the
IP changed while my computer was down (although it's down only
0.001% of the time).
--
Dan Aloni
[EMAIL PROTECTED]
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