Can I check my public ip. Is it real or simple NATing?

  • Hi,
        I m new in networking field and my question is how can I check my public ip.
    Because I have linkdotnet dsl modem connection (PPPOE). I requested to my isp for public ip and then he told me that only my ip not subnetmask and gatway.
    I call to my isp support center he can not explain me about my netmask and gatway.
    and I check my linkdotnet device interface my is same but my netmask and gateway is Is this possible netmask?
    when I attached my linkdotnet modem device direct to my pc it not browsing. So how can I check.
    I want to make ipsec vpn between my pfsense firewall.
    your answer will be very appreciated thanks in advance