Putty pauses until some input

[Utair Corporation]

Hello. I'm using Putty 0.63 to access all corporate routers (28xx, 29xx, 39xx, different IOSes) and stumbled into one common problem: if i launch some long running command like ping with many repeats or file operation then it runs for about 50 seconds and then just stops - nothing happening, no input from router, ping stops, file transfer stops etc.

If i hit any key it resumes! Though file operations get timed out if i notice too late.

Using other ssh clients do not have such problems. Also if i connect to Linux machine and then ssh from there, there is no such problem too.

Any ideas?

[Aman Soi]

Hi,

try downloading putty 0.64 and check .May be there are some caveats in 0.63.

what is the IOS version of boxes for which you are trying to do putty?

regds,

aman

[Utair Corporation]

0.64 - same issue

I cant say who's bug it is. I wiresharked, no traffic comes from cisco when it stops. tcp stack sends last ACK to packet from router and then... nothing else.

But why there is no such problem when using linux ssh client (openssh) ?

3945E IOS 15.3(3)M3 - has problem

3925E IOS 15.1(4)M7 - has problem

3750 IOS 12.2(55)SE8 - no problem

1721 IOS 12.4(16) - no problem

2811 IOS 12.4(24)T8 - no problem

smells like problem is with modern IOSes. Can someone check their 15.1, 15.3 routers?

[Aman Soi]

Hi ,

I could find bug but not exaclty related to the putty version and IOS u are using.

SSH Sessions disconnect when viewing logs w/ big oputput

CSCui94558

Description

Symptom:
SSH session is closed when viewing logs w/ big output.

Conditions:
When customer uses ssh version 2 and putty

Workaround:
Use xshell terminal

Known Affected Releases:

(1)

15.0(2)SG6

regds,

aman

[Utair Corporation]

I've seen it, but it is different.

In my case session is not closed and output resumes on input from my side.

I would blame putty, but, wiresharks indicates what it is IOS stops sending data.

[Utair Corporation]

Worked around by turning off null keep-alives. Socket keep-alives left on.

[Slim Backwater]

Thanks! Turning of sending of null packets worked for me with PuTTY 0.70. The setting is under Connection, Seconds between keepalives: 0.

[doresky]

Disabling keepalives (IE setting seconds between keepalives to 0) in putty resolved the issue between putty 0.77 and various Cisco switches.

[Georg Pauwen]

Hello,

what exactly is the solution ?

[Charles Hill]

Take a look at bug CSCui83823.

Any show command that gives a long output may close putty prematurely.

"Though file operations get timed out if i notice too late "

[Jerry Paul]

Hi,

Use Putty 0.64. Install it and check.

Jerry Paul

www.thenetworkhardware.com