Netgate 2100 ARP problem after replugging WAN port

somerino

Hei mike, I think you're right, it's not an ARP issue.
I've captured the traffic between the server and the gantner device and it literally only sends a phantom byte and closes the connection:

Even weirder, sometimes I can only see the tcp handshake without closing the connection.
The problem is so frustrating. I've mentioned below, that It might be VPN related. But I can't figure out, why everything else works through the VPN, except those gantner readers.
I've found a work-around by restarting the VPN manually. There comes the next problem. I've to do it everyday, because for some other silly reason, the VPN tunnel automatically restarts at night a few times.

Jul 27 22:12:42 WHQ-FW01 check_reload_status[414]: Reloading filter
Jul 27 22:12:43 WHQ-FW01 php-fpm[51938]: /rc.openvpn: Gateway, NONE AVAILABLE
Jul 27 22:12:43 WHQ-FW01 php-fpm[51938]: /rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use BUELACH_VPNV4.
Jul 27 22:26:00 WHQ-FW01 sshguard[87099]: Exiting on signal.
Jul 27 22:26:00 WHQ-FW01 sshguard[39533]: Now monitoring attacks.
Jul 27 22:35:46 WHQ-FW01 rc.gateway_alarm[38160]: >>> Gateway alarm: BUELACH_VPNV4 (Addr:10.0.0.2 Alarm:1 RTT:32.705ms RTTsd:2.141ms Loss:22%)
Jul 27 22:35:46 WHQ-FW01 check_reload_status[414]: updating dyndns BUELACH_VPNV4
Jul 27 22:35:46 WHQ-FW01 check_reload_status[414]: Restarting IPsec tunnels
Jul 27 22:35:46 WHQ-FW01 check_reload_status[414]: Restarting OpenVPN tunnels/interfaces
Jul 27 22:35:46 WHQ-FW01 check_reload_status[414]: Reloading filter
Jul 27 22:35:47 WHQ-FW01 php-fpm[51938]: /rc.openvpn: Gateway, NONE AVAILABLE
Jul 27 22:35:47 WHQ-FW01 php-fpm[51938]: /rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use BUELACH_VPNV4.
Jul 27 22:38:04 WHQ-FW01 rc.gateway_alarm[33071]: >>> Gateway alarm: BUELACH_VPNV4 (Addr:10.0.0.2 Alarm:0 RTT:23.979ms RTTsd:1.969ms Loss:5%)
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: updating dyndns BUELACH_VPNV4
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Restarting IPsec tunnels
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Restarting OpenVPN tunnels/interfaces
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Reloading filter
Jul 27 22:38:06 WHQ-FW01 php-fpm[375]: /rc.openvpn: Gateway, NONE AVAILABLE
Jul 27 22:38:06 WHQ-FW01 php-fpm[375]: /rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use BUELACH_VPNV4.Jul 27 22:38:04 WHQ-FW01 rc.gateway_alarm[33071]: >>> Gateway alarm: BUELACH_VPNV4 (Addr:10.0.0.2 Alarm:0 RTT:23.979ms RTTsd:1.969ms Loss:5%)
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: updating dyndns BUELACH_VPNV4
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Restarting IPsec tunnels
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Restarting OpenVPN tunnels/interfaces
Jul 27 22:38:04 WHQ-FW01 check_reload_status[414]: Reloading filter
Jul 27 22:38:06 WHQ-FW01 php-fpm[375]: /rc.openvpn: Gateway, NONE AVAILABLE
Jul 27 22:38:06 WHQ-FW01 php-fpm[375]: /rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use BUELACH_VPNV4.

mikedob

@somerino at this point I am unable to assist farther my knowledge of vpn connections is limited. You may want to repost this as a open vpn connections problems or change the thread title to get others to assist. Maybe stephenw10 can work with this new information and help

stephenw10

Do you have DCO enabled at the HQ end? Try disabling it again if so. There is a known issue some people are hitting with DCO where only the server side IPs are available and nothing beyond.

Steve

somerino

@stephenw10
I haven't activated this feature yet.
I just found out on a site note, that my ISP had maintenance work the last couple days. So this explains why the VPN tunnels had to reset.

Still I can't find an answer, what the difference is between an automatic reset and manual reset of the tunnel.

somerino

@mikedob

This thread is already getting out of hand. It started with ARP went to Spanning-Tree, to TCP protocol, VPN and I hope it will find an end soon.

Thank you for your help so far. By the way, the sonos problem isn't solved yet, I'll comeback at it, after this :D

stephenw10

Hmm, you have clients logs leading up the 'stuck in pending' state?

somerino

@stephenw10 not more than this. This was the last time I've seen something related to the mentioned VPN tunnel in the logs.
I think it's the same error state as I mentioned in the original problem. By replugging the WAN port, I tear down the VPN tunnel unexpectedly for the functioning part of the tunnel.
After a while both sides try to reestablish the connection

Client Side

Jul 27 22:35:47 	php-fpm 	345 	/rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use HQ_TO_BUELACH_VPNV4.
Jul 27 22:38:07 	rc.gateway_alarm 	1141 	>>> Gateway alarm: HQ_TO_BUELACH_VPNV4 (Addr:10.0.0.1 Alarm:0 RTT:24.269ms RTTsd:1.975ms Loss:5%)
Jul 27 22:38:07 	check_reload_status 		updating dyndns HQ_TO_BUELACH_VPNV4
Jul 27 22:38:07 	check_reload_status 		Restarting ipsec tunnels
Jul 27 22:38:07 	check_reload_status 		Restarting OpenVPN tunnels/interfaces
Jul 27 22:38:07 	check_reload_status 		Reloading filter
Jul 27 22:38:08 	php-fpm 	99524 	/rc.openvpn: Gateway, none 'available' for inet6, use the first one configured. ''
Jul 27 22:38:08 	php-fpm 	99524 	/rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use HQ_TO_BUELACH_VPNV4

Server Side

Jul 27 03:11:44 WHQ-FW01 php-fpm[41160]: /rc.openvpn: Gateway, NONE AVAILABLE
Jul 27 03:11:44 WHQ-FW01 php-fpm[41160]: /rc.openvpn: OpenVPN: One or more OpenVPN tunnel endpoints may have changed its IP. Reloading endpoints that may use BUELACH_VPNV4.
Jul 27 03:14:00 WHQ-FW01 sshguard[21891]: Exiting on signal.
Jul 27 03:14:00 WHQ-FW01 sshguard[55980]: Now monitoring attacks.
Jul 27 03:14:04 WHQ-FW01 rc.gateway_alarm[97993]: >>> Gateway alarm: BUELACH_VPNV4 (Addr:10.0.0.2 Alarm:0 RTT:26.625ms RTTsd:22.486ms Loss:5%)
Jul 27 03:14:04 WHQ-FW01 check_reload_status[414]: updating dyndns BUELACH_VPNV4
Jul 27 03:14:04 WHQ-FW01 check_reload_status[414]: Restarting IPsec tunnels
Jul 27 03:14:04 WHQ-FW01 check_reload_status[414]: Restarting OpenVPN tunnels/interfaces
Jul 27 03:14:04 WHQ-FW01 check_reload_status[414]: Reloading filter

stephenw10

There's only one client on that tunnel I assume?

With the server side assigned as an interface like that both sides reset when the link goes down because of the gateway failures. You might try disabling the gateway monitoring on the server side so it doesn't reset twice. There could be a timing issue.

Steve

somerino

@stephenw10 Yes it's a one client tunnel.
Can i disable it on the client side, I'd like to manage everything on one device.

Thanks Steve

stephenw10

That's worth testing. It's far more common to have the client side assigned though. I wouldn't expect that to cause a problem.

somerino

@stephenw10

I made the change you suggested. It improved the time it takes to reestablish the VPN connection, but I still have the "Waiting for response from peer" status on the server side.
(Client side is fine)

I think I've figured out the cause of my problem:

When the VPN tunnel breaks, some states remain in the FIN_WAIT_2 state, which won't allow a new tcp connection until it's been definitely closed.
Restarting the VPN tunnel kills the states and that's why it works as a solution.

Is there any way to automatically kill these states after a certain amount of time?

stephenw10

You can set 'State Killing on Gateway Failure' to 'Kill states for all gateways that are down' in Sys > Adv > Misc. As long as you have a gateway defined there it should kill those states.
Or you can set the TCP state timeout dircetly in Sys > Adv > Firewall&NAT. That set's it globally though.
However you can see there are states there for duplicate connections with different source ports. So it would be possible for that to open another state using a new source port with the old states still present.

Steve

somerino

@stephenw10
This makes it even more complicated.
So if it can create a new state, why doesn't it close the previous one.

I don't get it, why it doesn't close the tcp connection at all. why does it keep getting stuck at FIN_WAIT2

stephenw10

That's normal for TCP states. They will close when the state times out but if the firewall doesn't see the full close sequence between the end points it won't immediately close them. I don't expect that to cause a problem though since a new state will be opened with a different source port and that will be unaffected by any existing states.

Steve

somerino

@stephenw10
I think you're right.
I've set the Firewalll Optimization to normal, which should've set the time out for "FIN WAIT" to 900 seconds, but it still doesn't kill the state.
So I guess back to the roots to find out what the problem is.

EDIT
Well uhm, somehow it solved my problem automatically without restarting the VPN tunnel. I think the Firewall Optimization worked, need to do more testing though.