Solved

SCO Unix connectivity: Internet access via cable modem dropping

Posted on 2002-04-08
14
271 Views
Last Modified: 2013-12-23
Hi, not sure if this is right forum area for this but maybe someone can help or point me in the right forum direction:

I am working from home & connecting to a SCO unix server at work via my NTL cable modem, ie over the internet & I am using a VPN.

I don't have any trouble with any of the servers except one which insists on dropping my connection every time there is a pause in the network.  I have asked the techies at work to identify any timeouts set on the server but they don't know what they are looking for and are at a loss to help.  Waste of space actually.

Symptoms: All pc apps freeze for a short while (about 15-30secs) every so often at which time the sco box drops my connection.  All other servers, including another sco box do not.  

Anyone know what to look for so I can tell them in the office.  It's driving me crazy because as sods law would have it, it is the main server I use.

thanks
K

















0
Comment
Question by:Kyliem
  • 5
  • 3
  • 3
  • +1
14 Comments
 
LVL 38

Expert Comment

by:yuzh
Comment Utility
Hi Kyliem,

   What type of modem are you using (make and model), do you know what type of modem is direct connected to your SCO box?

   You can type to set you modem run in the Hays compatible modem, and use lower speed to see what happen.
please tell me which version of SCO is running at your server if you can.

=====
yuzh
0
 
LVL 16

Expert Comment

by:The--Captain
Comment Utility
See http://pcunix.com/Bofcusm/1246.html - the person there had the opposite problem, but I think the proposed solution appears quite relevant to your situation.

Just a guess, but it sounds like your keepalive settings are incorrect.  Try adjusting them (or disabling tcp keepalives).

This is not a problem with your cable modem, since you only have a problem with one remote machine.  I'm not sure how yuzh thinks you are going to be able to readily adjust the speed of your cable modem, why he thinks it is directly connected, or what use hayes compatibility is (I'd make sure is was DOCSIS compliant, but like I said, the problem is not your cable modem)

-Jon

0
 
LVL 38

Expert Comment

by:yuzh
Comment Utility
Hi The--Captain,

    Just for your interested, you can adjust the speed of the modem, connection establish time, or which communication standard it support (eg, flex56, v90 etc), by changing the register values (us AT command set), please refer to your Modem Manual for details, as we play with UNIX, we should always buy a modem with manual. For a modem to talk with one attached to a SCO box, it should have hardware control enable, and software control disable, other setting are vary from the made and model of the modems.

   Kyliem, please try The--Captain's suggesttion first, it it work, great! If not, we will try to do something in a hard way.

========
 yuzh  
0
 

Author Comment

by:Kyliem
Comment Utility
Sorry guys, was called away unexpectedly last week.  Will get around to this once I've found my feet again and award points as necessary.  Thanks for the help, I wasn't ignoring you.

K
0
 

Author Comment

by:Kyliem
Comment Utility
Thought no time like present.  I checked the settings and keepalives are set to their default of 7200 secs (2hrs) for tcp_keepidle and 75 secs thereafter for tcp_keepintvl.

So seems ok in that respect alhtough I understand from the man pages that the application can override these settings.  Possible I guess, I'll have to run some normal sessions and a couple of sessions with application running to see if there is a noticeable difference.

Thanks
K
0
 
LVL 16

Expert Comment

by:The--Captain
Comment Utility
yuzh - since you apparently don't know what a cable modem is, please refrain from further participation in this discussion.

Kyliem - try turning that 75 figure wayyyy up (or maybe setting it to zero will disable it altogether), and see if the problem either lessens in frequency or disappears completely.

Thanks,
-Jon

0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 

Author Comment

by:Kyliem
Comment Utility
Ok, thanks Jon, won't be able to test until late next week as I have to go away on personal business.  Therefore question may appear on hold for a while but i am not ignoring anyone.  
Thanks
K
0
 
LVL 16

Expert Comment

by:The--Captain
Comment Utility
Also, good point about the app being able to override the setting - maybe a review of the telnet (or telnetd) docs on the SCO system will reveal an available adjustment...

-Jon
0
 
LVL 38

Expert Comment

by:yuzh
Comment Utility
Please tell me what type of modem are you using at both end.
0
 
LVL 16

Expert Comment

by:The--Captain
Comment Utility
Cable modem on one end, and (I'm guessing here) ethernet on the other (probably has net access via T1, DSL, etc).

I'll let Kyliem confirm (or deny) this...

-Jon
0
 
LVL 16

Accepted Solution

by:
The--Captain earned 200 total points
Comment Utility
Kyliem - if you have access to a packet sniffer on both ends, you may want to turn it on in order to see which side is transmitting packets during the hang.  Also, you may be accidentally forcing a disconnect if you keep typing during the hang - this may allow the IP subsystem to "notice" that the other end is not responding, and cause it to shut down.

I rarely have problems keeping sessions alive during momentary disconnects, but only if I don't try to type anything...  In the old days ('92), I used to be astonished that I could be completely disconnected by my ppp server for several minutes, reconnect, and still be connected to the same session (as long as I didn't try to use it when it was down).

Cheers,
-Jon

0
 

Expert Comment

by:CleanupPing
Comment Utility
Kyliem:
This old question needs to be finalized -- accept an answer, split points, or get a refund.  For information on your options, please click here-> http:/help/closing.jsp#1
EXPERTS:
Post your closing recommendations!  No comment means you don't care.
0

Featured Post

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

Suggested Solutions

Title # Comments Views Activity
LAN or WAN ? 11 58
How to scan rdp  ''only'' open port 3333? 5 62
discontiguous network and EIGRP 12 34
Use of Training Budget 12 63
Don’t let your business fall victim to the coming apocalypse – use our Survival Guide for the Fax Apocalypse to identify the risks and signs of zombie fax activities at your business.
Meet the world's only “Transparent Cloud™” from Superb Internet Corporation. Now, you can experience firsthand a cloud platform that consistently outperforms Amazon Web Services (AWS), IBM’s Softlayer, and Microsoft’s Azure when it comes to CPU and …
Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now