Hi,
I'm trying to harden our firewall rules since they were a bit too loose :-).
So, I've got an good old DFL-800 and I've disabled: lan_to_wan1 -> allow_standard rule (you can send every packet to the net) and set allow (NAT) rules for main services: DNS, web, imap, pop, smtp, etc.
Everything works fine, except for a single thing.
We have a Relay SMTP server in our LAN.
- If a computer in the LAN uses a local IP: email is sent.
- If a laptop uses SMTP public IP the packet is dropped.
Log shows:
2012-06-21 17:34:17 Warning RULE 6000051 Default_Rule TCP lan <Private IP>-<Public IP> 3828-25 ruleset_drop_packet drop
So I thought: OK I've forgot to open SMTP port to the internet.
wan1_to_lan-> allow_smtp_nat NAT any all-nets core wan1_ip smtp
wan1_to_lan-> allow_smtp_sat SAT any all-nets core wan1_ip smtp
This seem to solve access from laptops outside our LAN, but when they are back on the LAN the problem persists.
Please ask for more info, if anything is not clear enough.
Thank you