USG 310/IPSec Error Packet(UDP) cannot be sent. reason: Network congestion

WiSy

Hello,

due to the current Homeoffice situation my company is running a lot more VPN Connections then usual.

Usually we are running about 6 or 7 IPSec IKE/IKev2 Site2Site Connections and about 5-10 IKEv2 Client2Site.

Now we have round about 20 additional Client2Site Connections and everything was running fine for 2 weeks until yesterday.

Suddenly some VPNs (S2S and C2S) disconnected and were unable to reconnect until we rebooted the firewall.

I noticed these Error in the Logs:

Any Ideas/suggestions?

Zyxel_Jerry

Hi @WiSy

Do you enable BWM on the device?

When the issue occurred, can you disable BWM function and chek if the symptom is still exist?

Zyxel_Jerry

Hi @WiSy

Do you enable BWM on the device?

When the issue occurred, can you disable BWM function and chek if the symptom is still exist?

WiSy

Hi @Zyxel_Jerry

I disabled BWM but issue still persists.

All IKE Site2Site get randomly dropped at the same time an are unable to reconnect until I reboot the Device.

IKEv2 Connections still working.

I noticed this entry in the log

Tunnel [IKE_NRW_Gateway:WISY-NRW:0x2c0aee2a] built successfully

41  2020-04-08 11:06:27 x.x.49.237:4500    x.x.184.39:4500

x.x.49.237 is the wrong IP for that Gateway, something is getting mixed up there.

Zyxel_Jerry

Hi @WiSy

Can you collect diagnose info and IKE log when the log displayed “network congestion and send it to us via private message?

Here is the step to collect diagnose info.

Go to Maintainance > Diagnostics > Diagnostics > Collect > Click Collect now

After 5~10 minutes 

Go to > Maintenance Diagnostics > Diagnostics > Files > Select the diaginfo > Click Download

Here is the step to collect IKE log

Go to Monitor > Log > View Log > select IKE category

Can you also provide remote access to the device via private message?