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New Member

dynamic vpn tunnel

I have a vpn tunnel setup with a PIX515 static ip on one end, and a pix501 with dynamic ip on other end.

Before the tunnel will come up you have to ping an ip behind the 515 from the 501. The 501 has to establish the tunnel since it has a dynamic ip.

Is there anyway I bring the tunnel up auto. without having to ping?

If the tunnel would go down for some reason, it might not come back on its own.

The device at the remote site is polled from HQ and doesn't try and talk back to HQ subnet, so the tunnel probably won't come back on its own.

Also is there anyway to update DYNDNS with a pix501

Cisco Employee

Re: dynamic vpn tunnel

You can get the 501 to send regular packets over the tunnel by configuring an NTP server on it. Set up an NTP server on your main network (any Cisco router can act as an NTP server if you don't have a Unix box), then point the 501 at it with the command:

clock timezone

clock summertime ......


This will make the 501 regularly send NTP packets to the main site which should keep the tunnel up. It has the added benefit of keeping all your syslogs in the correct time.

See the following links for command details:

And sorry, there's no way I know of to update DynDNS with a pix.

New Member

Re: dynamic vpn tunnel

How do I get the 501 to talk through the tunnel?

Subnet behind pix 515 is:

Subnet behind pix 501 is

If I try and ping an address on subnet from the PIX 501 console, I get no response, but if I hook a PC to the 501 it will bring the tunnel up and I will get a response.

NTP sounds like a good idea, if it can talk through tunnel.

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