ISDN call drops in the middle of SFTP transfer

yaminqureshi · ‎09-10-2008

Hi,

I have a problem doing SFTP through ISDN, ISDN connection is not staying active throughout the duration of the file transfer, it drops after its timeout value even if data transfer is in progress and file transfer break at that point, this happens with sftp transfer only, other type of connection like telnet, rdp works fine. Intresting traffic list I have define is,

access-list 112 permit ip host 10.10.10.9 any. All the traffic is orignating from IP address 10.10.10.9

Any suggestion on that.

Thank you

Yamin

Richard Burts · ‎09-10-2008

Yamin

The most common cause of ISDN dropping such as you desccribe is that the dialer-group and dialer-list do not include that traffic as interesting traffic. Your description of your dialer list sounds like it is interesting on your end. But is it also interesting on the other end? Do you know which end of the connection is dropping? It may be that the other end of the connection is dropping because of the configuration of the dialer list on the device on the other end of the connection.

HTH

Rick

HTH

Rick

yaminqureshi · ‎09-10-2008

Thanks for your reply Rick.

This connection is a one way connection initiating from my side only, SFTP connection bring up the call but call drops after its dialer timeout value. It is my end of the connection dropping.

Thank you

Yamin

Richard Burts · ‎09-10-2008

Yamin

I do not understand the comment that it is a one way connection. For SFTP how can it not be a two way connection?

Perhaps it would be helpful if you would run debug isdn q931 and post the output. You do not need debug during the entire time that the connection is up, but could start debug shortly before the connection will time out (or run debug the entire time but only post the output of a short interval before the connection drops and all the activity as the connection drops).

HTH

Rick

HTH

Rick

Giuseppe Larosa · ‎09-10-2008

Hello Yamin,

as Rick has pointed out also the called party has faculty to drop the ISDN call if the dialer timeout ends on it.

have the same config of the dialer-list on both ends.

If it is your end dropping this means that for your dialer list SFTP traffic is not interesting so post the dialer list config.

Hope to help

Giuseppe

yaminqureshi · ‎09-11-2008

Hi,

Dialer list I have on my side is,

access-list 112 permit ip host 10.10.10.9 any, all the traffic is orignating from 10.10.10.9. By one way connection I mean to say that call can be initiated from my side only (i.e from 10.10.10.9 which is my source) and thats why other side of the connection has no interesting traffic defined.

Very odd thingh I am observing is other trye of connections like telnet rdp ssh works fine and session do not break until i end my session irrespective of timeout value, even with sftp connection the isdn call is initiating but call drops after dialer timeout value. That lead me to feel after file transfer begin connection is no more taking transfer as interesting traffic even though I am using any for the destination in the dialer list. Is SFTP different from other type of connection.

Thank you

Yamin

Giuseppe Larosa · ‎09-11-2008

Hello Yamin,

I see two possible cases:

a) the SFTP is using a different IP source so does not match with the dialer list

b) actually the SFTP session is stucked for some reason and no packets flow after initial setup attempt and the dialer timeout will close the ISDN call

Hope to help

Giuseppe