Re: IP Lease
- From: Stephen Hoffman <Hoff@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Fri, 29 Jun 2007 12:46:12 -0400
Tom Linden wrote:
This is somewhat OT.
From home I use PuTTY SSH on an XP laptop through a wireless router attached to
Comcast cable to access the VMS cluster. If I go to another window for a while
and return to the VMS session the connection gets closed, so I tried opening
another window and ran a script which just loops endlessly
$ start:
$ sho time
$ wait 00:01
$ goto start
but it only keeps that window alive, so I guess that the two sessions have
different IPs. Don't suppose there is any way of doing this?
Not much to go on here, but this looks more like a keepalive setting somewhere, or some sort of a terminal or session timeout with a firewall or with your OpenVMS cluster. (And some OpenVMS boxes around do still run terminal timeout programs; idle-process killers, etc.)
Sessions do not typically have IP addresses. Your cable modem likely has an IP address, and probably one assigned by DHCP from your ISP here assuming you do not have static address(es) assigned by your ISP. Your laptop likely also has an IP address -- probably a private Class C address assigned from your cable model, or from your firewall, via DHCP.
The target OpenVMS box also likely has a static address. (Yes, you can use dynamic DNS...)
An ISP is unlikely to overtly blow off sessions, but it's certainly feasible for a host system or a firewall knock them off. (That written, there are reports and examples of ISPs implementing all manner of bizarre things.)
IP leases are also automatically renewed, and any self-respecting and functional DHCP client will know how and when to renew an IP lease. On Microsoft Windows, ipconfig/all will display the IP address and the lease and other details, IIRC.
Check whatever logs you have access to on your firewall, and on the target system and its firewall.
Do look to establish a VPN over the connection. Locally, I tunnel everything over Mac OS X SSH (http://64.223.189.234/node/134), when I'm up to this sort of connectivity. Various ssh clients have an option for TCPKeepAlive, for instance. Donno about PuTTY. There are also firewalls that can support VPNs, basically bridging your laptop or potentially your local network into the target network.
You will also want to look at trying something other than Windows itsef, as Windows has been known to blow off idle connections all by itself. We chased one example with FTP sessions getting nuked by a Windows timer some time ago. Try the connection with a Linux or Mac OS X or OpenVMS box as the client, for instance.
Also see http://64.223.189.234/node/275 for an introduction to operating OpenVMS within IP networks and particularly with firewalls.
--
www.HoffmanLabs.com
Services for OpenVMS
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- IP Lease
- From: Tom Linden
- IP Lease
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