VPN IPsec site-to-site disconnects

Nicola_Santalucia

Hello everyone. I have a site-to-site IPsec VPN between two Zyxel firewalls: USG Flex 100 and USG 110. It disconnects in randomly for no reason. Can anyone give me some advice? Thanks

Zyxel_Jeff

Hi @Nicola_Santalucia

For USG Flex series should download V5.36P2 firmware, you could download the firmware by this link. Thanks.

Nicola_Santalucia

Okay, I'll try it and let you know. Thank you.

17/07/23 I wanted to inform you that after updating the firmware of the USG Flex to version V5.37(ABUH.0)
and also that of the USG 110 to version 473AAPH2 the problem seems to be solved. I thank you very much.

Nicola_Santalucia

Zyxel_Jeff

Hi @Nicola_Santalucia

Welcome to the Zyxel community. We suggest you update the firmware to the latest version V5.36P2 for USG Flex100 and V4.73P2 for USG110 for further verification to see whether this symptom still occurs. You can download the firmware from this link: https://portal.myzyxel.com/my/firmwares
Thanks.

Nicola_Santalucia

Thank you for the kind response. The versions of both firewalls are already updated..V5.36P2 for USG Flex100 and V4.73P2 for USG110. Thank you

Nicola_Santalucia

Hello, have any of you encountered a similar problem?

mMontana

@Nicola_Santalucia does your firewall know which are the capabilities of the connection via WAN setting?

Configuration use any kind of BWM?

Is it possibile that one of your connections have sudden and short loss of bandwidth or connectivity?

Nicola_Santalucia

Thank you for your reply. 1. I didn't understand the question about the WAN. 2. BWM is not active, 3. No, my connections no have sudden and short loss of bandwidth or connectivity

Zyxel_Jeff

Hello @Nicola_Santalucia

Can you please confirm if the random VPN disconnection issue is still occurring? This problem might be caused by a Buffer overflow issue. We strongly recommend updating the USG Flex 100 to V5.36P2 and the USG110 to V4.73P2. Once updated, please check if the random VPN disconnection issue persists. Thanks.

https://community.zyxel.com/en/discussion/17102/buffer-overflow-issue-faq

Nicola_Santalucia

Thank you. On the USG 110 I have version 4.73(AAPH.2). On the Usg flex I have version 4.73(AAPH.2). Are they ok?

Zyxel_Jeff

Hi @Nicola_Santalucia

For USG Flex series should download V5.36P2 firmware, you could download the firmware by this link. Thanks.

Nicola_Santalucia

Okay, I'll try it and let you know. Thank you.

17/07/23 I wanted to inform you that after updating the firmware of the USG Flex to version V5.37(ABUH.0)
and also that of the USG 110 to version 473AAPH2 the problem seems to be solved. I thank you very much.