Someone trying to access my system

So I am working on setting up remote stations, I have open the correct ports in my firewall and used port forwarding in the firewall to make it work. But I see a lot of “weird” access attempts in the call logs. How can I stop them? I am new to this and would appreciate any help. I have closed the ports for now but it seems like i am still seeing unusual attempts in the log. Here is what i see

Call Date Recording System CallerID Outbound CallerID DID App Destination Disposition Duration Userfield Account
2017-01-16 09:22:56 1484580176.11927
ddddabc Congestion s [from-sip-external] ANSWERED 00:12
2017-01-16 09:21:05 1484580065.11926
ssssabc Congestion s [from-sip-external] ANSWERED 00:13
2017-01-16 09:19:18 1484579958.11925
aaaaabc Congestion s [from-sip-external] ANSWERED 00:13
2017-01-16 09:17:31 1484579851.11924
ppppabc Congestion s [from-sip-external] ANSWERED 00:13
2017-01-16 09:15:45 1484579745.11923
ooooabc Congestion s [from-sip-external] ANSWERED 00:13
2017-01-16 09:14:03 1484579643.11922
iiiiabc Congestion s [from-sip-external] ANSWERED 00:13
2017-01-16 09:12:08 1484579528.11921
uuuuabc Congestion s [from-sip-external] ANSWERED 00:13

and when i click on the system information on one of them i get this…

Time Event CNAM CNUM ANI DID AMA exten context App channel UserDefType EventExtra CEL Table
2017-01-16 10:02:34 CHAN_START 300003 300003 DEFAULT 0048222199466 from-sip-external SIP/96.31.14.118-000027ed
2017-01-16 10:02:34 ANSWER 300003 300003 300003 0048222199466 DEFAULT s from-sip-external Answer SIP/96.31.14.118-000027ed
2017-01-16 10:02:47 HANGUP 300003 300003 300003 0048222199466 DEFAULT h from-sip-external SIP/96.31.14.118-000027ed
2017-01-16 10:02:47 CHAN_END 300003 300003 300003 0048222199466 DEFAULT h from-sip-external SIP/96.31.14.118-000027ed
2017-01-16 10:02:47 LINKEDID_END 300003 300003 300003 0048222199466 DEFAULT h from-sip-external SIP/96.31.14.118-000027ed

Can someone help me understand what this all means and what i can do about it … Please.

Thanks

I think i got it… I turned off allow guest access in the system. Something i dont understand though is i also closed the ports on the firewall and i can still make call from my house. not sure why. but thats ok.