When I look at all the ports that are open on my computer, one of them is 53, which corresponds to DNS.
From what I understand about how DNS stuff works, my computer would normally have to ask someone else about domain name information - my ISP would be my DNS.
But if my DNS port is open (in a LISTEN state), then what does that mean? That I'm a DNS service to some other device? Are other phones on my WiFi trying to reach my computer first for DNS info before they get forwarded to the ISP's DNS, or what?
1 Answer
It means either your computer is running a DNS server (or proxy or it has been compromised and someone is using it as a mechanism to control/access your system).
If port 53 is only listening on your LAN it's likely you have some computer sharing going on and this woukd be normal on a router. If it is listening on a WAN interface you probably have a problem.
Are other phones on my WiFi trying to reach my computer first for DNS info before they get forwarded to the ISP's DNS, or what?
That depends on those devices. A DNS server cannot "attract" requests by merely running; devices need to be configured to use it first.
(But if you also run a DHCP server, it can provide such configuration automatically, just as with a normal home router.)
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