Test VPN server alive

plambrecht · Post by **plambrecht** » Mon May 24, 2004 5:47 am

Hi,

I need an UDP test to see if my Cisco VPN server (PIX and IOS based) are up and running.
Does anyone have an UDP string to send/receive ?
Ping is not an option, because I disable ICMP on my VPN server.

Anyone ?

Pieter

KS-Soft · Post by **KS-Soft** » Mon May 24, 2004 8:56 am

What about SNMP test? Or you have disabled SNMP protocol as well?

Regards
Alex

plambrecht · Post by **plambrecht** » Mon May 24, 2004 9:05 am

KS-Soft wrote:What about SNMP test? Or you have disabled SNMP protocol as well?

The VPN server is published on the internet, and only accessible through the internet. SNMP is not an option.
A UDP packet looks like the only solution to me.

thx anyway for this reply.

Pieter

boxy_25 · Post by **boxy_25** » Tue May 25, 2004 12:25 am

Hi,

I think you can open icmp port only for one station (the monitoring station) and block for all the other. You can also allow only "echo request" to securise at maximum.

Cédric.

plambrecht · Post by **plambrecht** » Tue May 25, 2004 3:24 am

[quote="boxy_25"]I think you can open icmp port only for one station (the monitoring station) and block for all the other. You can also allow only "echo request" to securise at maximum.
quote]

the thing is, I don't want to check ICMP, but VPN.
There always is a possibility that the ICMP works, but that de VPN service is down...

boxy_25 · Post by **boxy_25** » Tue May 25, 2004 3:38 am

HI,

"There always is a possibility that the ICMP works, but that de VPN service is down..."

That depend wich IP you monitor...

If you monitor your internet IP, that's true, you cannot see if VPN is UP
But your VPN is connecting 2 network with different IP range (ex 10.1.0.0 and 10.2.0.0). if there is a computer in 10.1.0.0 that ping 10.2.0.1., you can see if VPN is UP.
You can monitor 2 or 3 IP in the distant network so if they are all dead, the VPN is dead.

Cédric

plambrecht · Post by **plambrecht** » Tue May 25, 2004 5:20 am

Your suggestion implies that I make a VPN conncetion and then ping a server of the remote network.
But that is not what I want.
I just want to check if the VPN service is alive bij 'portscanning' the UDP/500 port.
For that I need the UDP packet to send/receive...

Pieter

KS-Soft · Post by **KS-Soft** » Tue May 25, 2004 2:59 pm

UDP port #500?
ISAKMP protocol http://www.networksorcery.com/enp/protocol/isakmp.htm
?

Regards
Alex

plambrecht · Post by **plambrecht** » Wed May 26, 2004 2:07 am

Cool site..
Apparently it is not as easy as I thought... No fixed header.. darn..

thx anyway.

Pieter

ericm · Post by **ericm** » Mon Jun 07, 2004 9:37 am

If you find something please post it.

Test VPN server alive

Test VPN server alive

ICMP

Re: ICMP

ICMP

Test VPN