Solved SBS 2011 loses internet every 60 seconds

December 27, 2011 at 21:00:23
Specs: SBS 2011, Dual Quad Core Xeon, 16Gb EEC ram
I have a SBS 2011 Server with 2 NICS. 1 NIC (10.10.10.2) is connected to a Cisco router (10.10.10.1) with NAT internet access. The other NIC (10.10.20.2) is connected to the LAN and the LAN gets its Internet connection thru the SBS server in this way. This all works perfectly.

The issue is that exactly every 60 seconds I lose internet connection for between 2 - 20 seconds.

Another server(10.10.10.3) also connected directly to the Router has no dropout. Also pinging 10.10.10.2 from the second server also has no dropout.

Pinging the router from 10.10.10.2 shows the dropout.

I have been unable find what is causing this dropout.
Hard drive times are all normal.
Full virus & Malware scans have shown nothing.
Network traffic is minimal. These dropouts are playing havoc with our RDP connections into the network.
Someone please help.


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✔ Best Answer
January 11, 2012 at 06:54:48
I would suspect a malfunctioning nic in the server.

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#1
December 28, 2011 at 07:35:55
Is there anything in the event viewer?

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#2
December 28, 2011 at 15:05:24
No ... 1st place I checked ...

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#3
December 28, 2011 at 15:47:51
what happens when you ping 10.10.10.2 from 10.10.10.3?

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Related Solutions

#4
December 28, 2011 at 16:38:32
Good thinking! Most people don't look there. I was never a fan of 2 NICs in Windows.

Anyway, I read your first post about 10 more times & it's sounds like all internal connections are being maintained but the internet is being lost on that second NIC.

In other words, it's a one way loss & that one way is to an external IP. So, the router has to be dropping it. If Windows were dropping it on the second NIC, pinging the first server from the second server would drop also.

Does that make sense? Now it's time to open the router interface & watch the status. Does it change at those intervals? Are there any log files in the router to view?

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#5
December 28, 2011 at 16:50:49
works fine

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#6
December 28, 2011 at 17:22:47
10.10.10.3 to 10.10.10.1 experiences no dropouts.
If it is the cisco, then it is only the route to 10.10.10.2 that is affected.

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#7
December 29, 2011 at 12:05:17
I am not seeing a answer to pinging .2 from .3

Please post the following info

tracert yahoo.com
from a pc attached to the sbs

tracert yahoo.com
from the sbs

nslookup 10.10.10.2
done from a pc

nslookup 10.10.20.3
done from a pc

You say you lose internet for 2-x seconds. don't you mean ping fails for that time? After all you state pcs going thru the sbs have no issues, right?

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#8
December 29, 2011 at 16:16:59
There is no answer at all for 10.10.10.2 to 10.10.10 .3 I would asume that this is because that subnet is only connected to the cisco and not thru a switch. Then again 10.3 can reach 10.2. How strange.

The tracert from SBS server .2
Tracing route to yahoo.com [209.191.122.70]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms 10.10.10.1
2 * 1 ms 1 ms gigabitethernet1-22.lon73.melbourne.telstra.net
[165.228.108.97]
3 4 ms 1 ms 2 ms tengigabitethernet0-12-0-2.exi-core1.melbourne.t
elstra.net [203.50.80.1]
4 20 ms 19 ms 19 ms bundle-pos3.chw-core2.sydney.telstra.net [203.50
.11.14]
5 18 ms 19 ms 19 ms bundle-ether1.oxf-gw2.sydney.telstra.net [203.50
.6.90]

I am unable at this stage to do lookups from a workstation (they are all switched off) as the office is closed for the holidays and I am working from home. I have updated the cisco and switched the VPN to the other server for staff remote access. That is now working correctly with no dropouts.


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#9
December 31, 2011 at 09:35:59
the lan ports on the cisco are a switch.

"no answer at all for 10.10.10.2 to 10.10.10 .3"

would possibly indicate a firewall issue on .3

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#10
December 31, 2011 at 23:36:42
10.3 has no issues at all ..... I have currently redirected the VPN thru it whilst I try and sort out 10.2
swapped port 1 & 2 around on Cisco today.
No change ... this eliminates a hardware fault on the Cisco.

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#11
January 3, 2012 at 10:53:15
vpn on 10.3?
vpn can render the nic useless to all other non vpn traffic.

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#12
January 3, 2012 at 21:34:03
It is an incoming VPN not outgoing ... anyway, I have disabled Routing & Remote Access Services .. No change .. still dropping out every 60 seconds.

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#13
January 4, 2012 at 10:44:41
and the tracerts requested?

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#14
January 10, 2012 at 18:37:06
traceroutes would be very useful.
Every 60 seconds sounds like an update, routing update, could be a routing protocol is running on the network.

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#15
January 11, 2012 at 02:07:49
OK ... I have given up on this one .... I have gone thru every possible service and running program and tried switching them off. No luck ....
I have abandoned the routing data thru the SBS server and turned off the offensive interface. Hooked the Cisco directly to the LAN and changed its NAT to run directly to 10.10.20.0
Everything is now running perfectly !!!!!

Thanks for the sounding board .... I suppose you sometimes have to cut your losses time-wise and take 2 steps back to be able to move forward to a satisfactory conclusion.


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#16
January 11, 2012 at 06:54:48
✔ Best Answer
I would suspect a malfunctioning nic in the server.

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#17
January 11, 2012 at 15:27:51
it just occured to me that the nic in question is also used by the bios for remote management (Supermicro motherboard) ... maybe something funny is going on there.

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