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snmp monitoring

I have a situation where i need to do snmp monitoring from a central location to a number of remote site servers, switches, routers etc. I originally set this up via ipsec vpn's between the central site c1841 and the remote site pix 501 and 506's, and c1800's. The ipsec vpn's will renegotiate their sa's and when doing this will drop the vpn and then false positives will be generated. Have tried to resolve this with keepalives and other methods but it still happens. I've also done this through assigning a static nat translation on the remote site and opening up the router/firewall for snmp(udp 161)from our central location and this works with no issues. I'm wondering if i need to be concerned about security with this method. The data being transferred is device statistical information and status and i'm assigning the snmp level as read only on a different community name than the default. wondering if this is an accepted method and how most people do this

Reply to
mmark751969
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Maybe you need to look into your dropping vpn problem, as this is not what I usually experience. The vpn keeps working all the time.

Reply to
Rob

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Thanks. what are your end devices.

Reply to
mmark751969

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3725, 1721, 877, 887, Draytek 2600, 2800 all with IPsec vpn.
Reply to
Rob

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My recollection is that in good time before the SAs time out a new one is negotiated and the traffic then switches to the new SA, well before the previous SA is closed.

Perhaps you have some weird timeouts configured that is breaking that mechanism?

I have only ever used the defaults and as long as there is regular traffic they never go down.

Maybe of course if the polling interval is long, then the SAs are going down since there is no traffic. In that case there will be a delay establishing a new SA which could result in an snmp timeout since it takes a while for the crypto to get its head together.

There is probably a setting to stop the SA going down even if there is no traffic or you could create sufficient traffic so that it does not go down. There are many options to create some traffic nowadays.

- SAA poll - ntp - turn up your snmp frequency

Reply to
bod43

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Thanks. I'll try increasing snmp polling frequence. right now it's at two minutes. I'll decrease that. Thanks

Reply to
mmark751969

At two minutes there should be no problem whatsoever. The typical IPsec SA lifetime is one hour.

I have SNMP polling every 5 minutes (by MRTG) and at some irregular intervals by other scripts, and I see no problems.

There must be something wrong with your VPN config. When you have configuration for time values, remove it all. The defaults should work OK.

Reply to
Rob

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