I'm looking at the settings in my TP-LINK WDR4300 router and noticed settings for VPN passthrough and ALG. Every single option is enabled but I am hoping someone can help me understand these settings and what they do and whether or not I should leave them enabled. I am pretty sure none of this applies to me.
Thanks in advance in case I am not able to finish the account sign up on this site. I asked a question a few weeks ago but my email never responded and I was not able to respond to the helpful people.
VPN - VPN Passthrough must be enabled if you want to allow VPN tunnels using VPN protocols to pass through the Router.
PPTP Passthrough - PPTP Passthrough. Point-to-Point Tunneling Protocol (PPTP) allows the Point-to-Point Protocol (PPP) to be tunneled through an IP network. To allow PPTP tunnels to pass through the Router, click Enable.
L2TP Passthrough - Layer Two Tunneling Protocol (L2TP) is the method used to enable Point-to-Point sessions via the Internet on the Layer Two level. To allow L2TP tunnels to pass through the Router, click Enable.
IPSec Passthrough - Internet Protocol security (IPSec) is a suite of protocols for ensuring private, secure communications over Internet Protocol (IP) networks, through the use of cryptographic security services. To allow IPSec tunnels to pass through the Router, click Enable.
ALG - It is recommended to enable Application Layer Gateway (ALG) because ALG allows customized Network Address Translation (NAT) traversal filters to be plugged into the gateway to support address and port translation for certain application layer "control/data" protocols such as FTP, TFTP, H323 etc.
FTP ALG - To allow FTP clients and servers to transfer data across NAT, click Enable.
TFTP ALG - To allow TFTP clients and servers to transfer data across NAT, click Enable.
H323 ALG - To allow Microsoft NetMeeting clients to communicate across NAT, click Enable.
RTSP ALG - To allow some media player clients to communicate with some streaming media servers across NAT, click Enable.
SIP ALG - To allow some multimedia clients to communicate across NAT, click Enable.