I want my Mac to receive encrypted email via POP3 on port 995, and I want to send encrypted email using SMTP on port 465 and 587 (two different ISP providers). The Westell 7500 DSL modem fails to perform the port triggered forwarding required to allow this.
I’m using the Westell A90-750015-07 modem router with the red/black theme on the web configuration screens. I want to use a trigger so that when my Mac sends to port 995, the firewall allows sends back from my ISP port 995.
Wireshark confirms the SSL encrypted email conversations happily happen with my ISP and my email transfers both ways with the Mac firewall running.
However, the 7500 router only allows port 995 traffic when set to “Minimum Security (Low)” or “No Security (None)”. The router is suppose to allow “Typical Security (Medium)” along with specific port forwarding and triggers that are designated. But it does not.
Wireshark confirms that my email program initiates a conversation to the email server port 995 from a high port (62xxx), but nothing comes back. Either the router blocks the port when my computer sends it outbound or the router blocks when my ISP email server sends back a packet from that port.
Same thing happens when I create a local email that needs to be sent out via SMTP. I have 2 different ISPs that use SSL encrypted SMTP traffic on ports 587 or 465. For the first one, Wireshark shows that my Mac starts a conversation to port 587 and repeats 10 times before giving up. If I set the Westell 7500 to “Minimum Security” the email transfers up to my server no trouble: my Mac sends from a 62xxx port to 587 and my ISP server responds from port 587 back to the same high port.
If I use the other ISP which uses a different SSL SMTP port, the same thing happens. After 10 tries, the Mac quits trying with an error message, “The connection to the server ‘xxx.yyy.com’ on port 465 timed out.” Setting the modem to “Minimum Security” lets the email transfer out using a port 465 exchange. My Mac sends out from a high port 62xxx to port 465 and the ISP responds from port 465 to the same high port.