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Beginner

Disable an ECHO on the TELNET session.

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

...

Everyone's tags (6)
1 ACCEPTED SOLUTION

Accepted Solutions
Beginner

Cisco IOS telnet-server doesn

Cisco IOS telnet-server doesn`t support ECHO negotiations. It`s a bug.

View solution in original post

2 REPLIES 2
Beginner

Cisco IOS telnet-server doesn

Cisco IOS telnet-server doesn`t support ECHO negotiations. It`s a bug.

View solution in original post

Beginner

Hello!

Hello! Thanks for the answer. We have an own provisioning system has been supposed to performs inter-operation with a CDMA PDSN equipment, so a reducing of response traffic (from PDSN) and down a latency of command execution - are very important for us. What we can do to initate a bug fixing ?
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