Hi,

I have a firewall based on ipchains,

I placed it open to anything to test a software that needs access via some ports: TCP 4662 UDP 4672.

ipchains -L shows as follow:
$ ipchains -L

Chain input (policy ACCEPT):
target prot opt source destination ports
- icmp ------ anywhere anywhere any -> any
- udp ------ anywhere anywhere any -> any
- tcp ------ anywhere anywhere any -> any
Chain forward (policy MASQ):
target prot opt source destination ports
- icmp ------ anywhere anywhere any -> any
- udp ------ anywhere anywhere any -> any
- tcp ------ anywhere anywhere any -> any
Chain output (policy ACCEPT):
target prot opt source destination ports
- icmp ------ anywhere anywhere any -> any
- udp ------ anywhere anywhere any -> any
- tcp ------ anywhere anywhere any -> any

but the software keeps telling that the ports aren't open,

My suspition now are towards the CPE /ADSL router.

Is there a way to test which ports are passing through the CPE and which arent?

thanks

I suppose you already tested with
telnet <ip-address> port,
(or site name if you are sure your DNS works)
and with traceroute.
There is a way to put every blocked packed in a log file by adding -log-level nn in the iptables commands.