USG110 IpSec VPN Issues

ETSTECH

Hello, I have a strange issue on a site-to-site VPN scenario, using 2 USG-110. The issue is that, normally once a week or more, the bandwidht goes incredibly down on the tunnel, and only if I reboot twice (because the firt reboot don't work) both the USGs, I can solve the issue. Can anyone help me understand what can cause the issue? Thanks.

Zyxel_Jeff

Hello @ETSTECH

(1). What is your firmware version of those two USG110s respectively?
(2). What are your ISP WAN UL and DL bandwidth for the two sites?
(3). While "the VPN tunnel bandwidth goes incredibly down", can you ping to the remote site subnet successfully? Or, did the symptom bandwidth goes incredibly down and speed slow only?
(4). What is the VPN throughput during this symptom occurs?
(5). Is there any error or blocked log(such as ADP blocked message) that can be observed on the Monitor > Log > View Log ? 
Thanks.

ETSTECH

Hello Jeff,

(1) The firmware on both the USGs is the latest, V4.73AAPH.0

(2) For the two sites we got 130Mbps DL 27Mbps UL

(3) When I got the issue, I can still ping both sides, with increased latency

(4) During the symptoms the VPN throughput is about 3Mbps both DL and UL (while normally is 16Mbps both)

(5) There are no errors on the log, referring to the VPN

Thank you.

Zyxel_Jeff

Hi @ETSTECH

OK, we could arrange a remote session to check it. I will inform you by private message, thanks.