Configuration snippets:
vlan 80 name untrusted by port
untagged ethe 3/1/3
ip access-group untrusted in
interface ve 80
ip address 192.168.80.2/24
ip access-list extended untrusted
enable accounting
sequence 10 permit tcp any 192.168.0.0/16 established
sequence 20 permit icmp any any
sequence 30 permit udp any host 192.168.255.2 eq dns
sequence 40 permit tcp any host 192.168.255.2 eq dns
sequence 50 permit udp any host 192.168.255.1 eq ntp
sequence 60 permit tcp any host 192.168.64.113 eq ssl
sequence 70 deny tcp any 192.168.0.0/16
sequence 80 deny udp any 192.168.0.0/16
sequence 90 permit tcp any any
sequence 100 permit udp any any
System attached to 3/1/3 has IP address 192.168.68.200/24, with its gateway set to 192.168.80.2.
With the above access-list that system is able to open TCP connections to 192.168.1.1, even though the initial SYN packet should not count as 'established'. If I remove the sequence 10 filter from the access-list, the system is no longer able to open such connections.