02-25-2014 06:53 AM - edited 03-03-2019 07:17 AM
Hello, All!
I have a some task to executing commands sent over TCP/Telnet connection from my apps to a Cisco device. So, I'd like to reduce/stop any output from the device as answer to input. I have tried to use IAC DO GA and DONT ECHO but it looks like that the device are ignore at all it.
Any advice or what I'm need to check additionaly?
Some illustration of what I'm doing in the apps:
Establish a TCP connection to the Cisco device
Received: 'FF FB 01 FF FB 03 FF FD 18 FF FD 1F' from Cisco device
Sent : TN$CMD_IAC, TN$CMD_DO, TN$OPT_GA,
TN$CMD_IAC, TN$CMD_WILL, TN$OPT_ECHO,
TN$CMD_IAC, TN$CMD_WILL, TN$OPT_TTYPE,
TN$CMD_IAC, TN$CMD_WILL, TN$OPT_NAWS,
TN$CMD_IAC, TN$CMD_SB, TN$OPT_NAWS, 0, 132, 0, 42,
TN$CMD_IAC, TN$CMD_SE,
TN$CMD_IAC, TN$CMD_WONT, TN$OPT_XDLOC,
TN$CMD_IAC, TN$CMD_WONT, TN$OPT_NEWENV,
TN$CMD_IAC, TN$CMD_WONT, TN$OPT_ENV, 13, 10,
TN$CMD_IAC, TN$CMD_SB, TN$OPT_TTYPE, 0, 'P', 'C', 'F', '/', 'D', 'R', 'V', '/', 'P', 'D', 'S', 'N',
TN$CMD_IAC, TN$CMD_SE,
/*
** Follows replies to the ciscoiacs
*/
TN$CMD_IAC, TN$CMD_DO, TN$OPT_GA,
TN$CMD_IAC, TN$CMD_DONT, TN$OPT_ECHO,
TN$CMD_IAC, TN$CMD_WONT, TN$OPT_ECHO,
44:50.29 XMIT 100 bytes BG7159: 172.16.0.45,14333 -> 89.253.0.8,23
ESTBLSHD SEQ=2266844313 D=60 ACK=1780728895 W=61440 CTL=PSH!ACK
DATA=FF FD 03 FF FB 01 FF FB 18 FF FB 1F FF FA 1F 00 *................*
84 00 2A FF F0 FF FC 23 FF FC 27 FF FC 24 0D 0A *..*....#..'..$..*
FF FA 18 00 50 43 46 2F 44 52 56 2F 50 44 53 4E *....PCF/DRV/PDSN*
FF F0 FF FD 03 FF FE 01 FF FC 01
Sent after login sequence:
44:51.29 XMIT 49 bytes BG7159: 172.16.0.45,14333 -> 89.253.0.8,23
ESTBLSHD SEQ=2266844395 D=9 ACK=1780728981 W=61440 CTL=PSH!ACK
DATA=FF FD 03 FF FC 01 FF FE 01 *.........*
44:51.49 RCVD 40 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780728981 D=0 ACK=2266844404 W=4037 CTL=ACK
And nothing getting back. After issuing:
49:19.24 XMIT 86 bytes BG7159: 172.16.0.45,14333 -> 89.253.0.8,23
ESTBLSHD SEQ=2266844578 D=46 ACK=1780729359 W=61440 CTL=PSH!ACK
DATA=43 4C 45 41 52 20 43 44 4D 41 20 50 44 53 4E 20 *CLEAR CDMA PDSN *
53 45 53 53 49 4F 4E 20 4D 53 49 44 20 32 35 30 *SESSION MSID 250*
30 39 39 30 31 33 35 31 35 30 36 34 0D 0A *099013515064..*
I don't want to receiving follows:
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729359 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=43 *C*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729360 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=4C *L*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729361 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=45 *E*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729362 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=41 *A*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729363 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=52 *R*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729364 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=20 * *
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729365 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=43 *C*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
ESTBLSHD SEQ=1780729366 D=1 ACK=2266844624 W=3817 CTL=PSH!ACK
DATA=44 *D*
49:19.24 RCVD 41 bytes BG7159: 89.253.0.8,23 -> 172.16.0.45,14333
...
Solved! Go to Solution.
03-21-2014 01:41 AM
Cisco IOS telnet-server doesn`t support ECHO negotiations. It`s a bug.
03-21-2014 01:41 AM
Cisco IOS telnet-server doesn`t support ECHO negotiations. It`s a bug.
03-21-2014 02:00 AM
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