Do you have any VPN connectivity in the same firewall.
If not, then somebody is trying to spoof your network.
You should protect your network by configuring ip spoofing in your firewall.
The IP Spoofing feature uses the Unicast Reverse Path Forwarding (Unicast RPF) mechanism, which dictates that for any traffic that you want to allow through the security appliance, the security appliance routing table must include a route back to the source address.
If for example our inside interface connects to internal network 192.168.1.0/24, this means that packets arriving at the inside firewall interface must have a source address in the range 192.168.1.0/24 otherwise they will be dropped (if IP Spoofing is configured).
To enable IP Spoofing protection, enter the following command:
CiscoASA5500(config)# ip verify reverse-path interface "interface_name" For example, to enable IP spoofing on the inside interface, use the following command:
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...