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New Member

On demand ping, NEED HELP!!!

Dear all NetPro gurus,

I have a WAN scenario with the following scenario:-

Site A ( ----- WAN ----- Site B (

This is what happens:-

At the beginning of day, doesn't matter what the user did at Site B (, he can't ping

Now if I goto Site A and from (which is a server), i ping to, then from that point onwards, Site B can ping to Site A and everything works.

HOWEVER, after next day, everything resumes to before and the scenario repeats that Site B can not ping Site A again until Site A initiate the ping again.

Have anyone see this before???



Cisco Employee

Re: On demand ping, NEED HELP!!!

Is site-A and site-B connected via VPN?

If they are, what type of VPN is it?

IPSec site-to-site VPN? static to dynamic or static to static site-to-site VPN?

If it's IPSec dynamic to static, only the dynamic site can initiate the VPN connection towards the static site. Base on your description so far, it sounds like that.

If it's IPSec VPN, check the lifetime configured, you can make the lifetime longer so the VPN tunnel stays up longer so the static site can still access the dynamic site.

New Member

Re: On demand ping, NEED HELP!!!

it is a static site-to-site VPN.

Also at Site A, there is another server at IP, which does NOT have this problem and can be ping and connect to by Site B whenever Site B wants to.  No need to pre-ping from Site A.

Would greatly appreciated your help.



Cisco Employee

Re: On demand ping, NEED HELP!!!

What device is it? Can you share the config?

Is it a stateful firewall? How is the NAT being configured?

Hall of Fame Super Blue

Re: On demand ping, NEED HELP!!!


With the greatest respect you shouldn't post this in both the firewalling an LAN Routing & Switching as it just creates confusion and can waste people's time. In additon on LAN R&S you made no mention of a VPN tunnel and there was no reason we would ask about it as we are dealing with LANs.

I'll post back to the LAN R&S and link it through to here as it seems more appropriate for this forum.


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