Site to Site VPN Issue .

MediComp

We Have two offices one is Head Office we Call As Site A and the Other is Branch Office we Call as Site B.

TZ 500 wireless-AC this is Firewall Model in Site A {Head Office}

TZ 400 wireless-AC this is Firewall Model in Site B {Branch Office}

We Are Connecting regularly from Site A Server to Site B Server, Few Day Back Public IP Address has Changed in Site B, We also Changed the IP Address in the Site A Firewall.

When We Observed the VPN Tunnels in both Sites it's Showing UP and In the Active Tunnel List, it Shows up.

But When we Ping from Site A to Site B It's Showing Destination is unreachable.

But when We Ping From Site B to Site A it's Pinging.

Any One Please Help Me To Fix this Issue?

Thank You

jward

I would suggest taking a packet capture on both firewalls to see if the Ping is being dropped on one side of the VPN. If so you may need to check the LAN to VPN or VPN to LAN (Or whatever Zone the traffic is flowing to or from) access rules. Try adding a new rule to see if this resolves the issue. You may need to move an access rule closer to the top of the list if there is another rule ahead of it that supersedes the rule you created.

https://www.sonicwall.com/support/knowledge-base/how-can-i-setup-and-utilize-the-packet-monitor-feature-for-troubleshooting/170513143911627/

If this does not correct the issue, you may need to open a case with support for live troubleshooting.