TTL mangle - how to identify port?

[spammagnet]

I'm editing the firewall rules on my GL-AR750S to hack the TTL for Visible using VZWINTERNET. (I upgraded my Visible account.)

My Slate router is connected on the WLAN port to the LAN port of a Netgear LM1200 modem. I get how to add a custom firewall rule but don't know how to identify the port to be specified in the command line.

I don't think it matters but the modem is in router mode with DHCP off and the Slate router has a static IP.

[spammagnet]

Addendum: If I add an iptables firewall rule with the port omitted, I get the desired speed on all connected devices. Without the added line, I get 5 Gbps. I get no traffic when I include WWAN0 as the port. (It's connected on that port and the router is configured with it being in WAN mode).

I have no idea if the name of the port actually is WWAN0, which I saw in another thread. I also have no idea how to identify the ports. Nothing's connected to the other ethernet ports. All connections are WiFi.

Does running the rule without a port specified have any undesirable effects?

[jericsmith]

If you SSH into the device just run 'IP a' and that will spit all the interfaces and their names for you.