Bravo2zero_sps

The basic answer is no you are not allowing external ips through as the 192 address is a non internet address, ie its used for home networks/small office network addressing etc. Its an internal ip range of addresses that don't appear/work on the internet, ie your routers ip address as it appears on the internet is the isp's ip address they give you, not one of your 192 addresses. Your 192 addressing is only applicable to your lan side of your router.

Someone trying to get into your network will have their ISP assigned ip address for the outside world, ie their address on the internet and will be from a pool of ip addresses owned by the ISP and can never be a 192 address.

However hackers have all sorts of ways around this through spoofing ip addresses and mac addresses where they make their details actually appear as something else. This is why firewalls and using routers is so important as a defence against this.

Hacking is a little like car crime though, if they are an expert and are determined there is normally a way they will know to get their end result.