DEFAULT PORT FOR SURGEMAIL SOFTWARE
DEFAULT PORT FOR SURGEMAIL PC

DEFAULT PORT FOR SURGEMAIL SOFTWARE

Added software complexity and non-deterministic functionality from a given input set (what passes the filter today may not be what passes the filter tomorrow).

Reliance upon an easily spoofed protocol.

There are several reasons for this that I have covered before. Per our discussion in the comments, it sounds like you may be confusing the role of a firewall with that of a transparent proxy.ДЇirewalls do not rely upon DNS resolution to implement access policies. Is there a solution in Cisco IOS that handles this? Is there an obvious solution I should know about, or is this simply an unusual firewall setup? I've not heard of IOS running a DNS server. Is there an application for Linux or Illumos that already does DNS-triggered IP whitelisting? (keeps me from re-inventing the wheel) Does this sound reasonable, or will there be inevitable issues with ipfilter not recognizing changes immediately? I'm pretty sure ipfilter will work with a Linux/Illumos NAT. I think that I can accomplish items 1-3 with ipfilter, combined with a custom-written DNS server to handle the whitelist, and trigger the additions to ipfilter. In this way, we can prevent accessing a non-whitelisted site that may exist on a shared, whitelisted IP.

(optional, but preferable) sniff the TCP connection to verify the hostname of the HTTP or HTTPS connection.

DEFAULT PORT FOR SURGEMAIL PC

If a PC initiates a connection an arbitrary IP address, which was not listed on any of the approved DNS responses, then arbitrary packets can be refused.If the DNS lookup was allowed, then the IP access list is immediately updated with the most recent results from DNS. The firewall server compares this to a whitelist of hostnames, and if it is permitted then the resulting IP addresses are passed back to the PC. The user's PC performs a DNS lookup for a given site (i.e. Here's what I want to happen: (outgoing connections, from a user on my network) I'm thinking that using a server will give me more flexibility, but I'm open to suggestions. This can either be Cisco IOS, a recommended alternative, or an actual Illumos or Linux server. I also want the same device to act as the DNS server that my PCs use so it always knows the latest IP for any hostname on the whitelist when a PC is trying to connect to it. However I want the outgoing connections to use a whitelist of hostnames. This is going to include your usual NAT, with port-forwarding for incoming connections. I am interested in setting up a firewall.

Default port for surgemail