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Yur

2 years ago

in Security: How Network Ports Work on danielmiessler.com | grep understanding
Ahhh, I see now.

So this (from lsof) makes more sense now:

firefox-b 250 yur 43u IPv4 0x4177018 0t0 TCP 10.0.0.102:53475->ar-in-f104.google.com:http (ESTABLISHED)

Firefox has an open connection with Google using my local port 53475, right? I guess outbound connections pick a random port and make sure it isn't in use or something? I assume there is a nice POSIX system call for this sort of thing? get_an_unused_user_port() sort of thing?

Thanks for the info.

2 years ago

in Security: How Network Ports Work on dmiessler.com | grep understanding
Ahhh, I see now.

So this (from lsof) makes more sense now:

firefox-b 250 yur 43u IPv4 0x4177018 0t0 TCP 10.0.0.102:53475->ar-in-f104.google.com:http (ESTABLISHED)

Firefox has an open connection with Google using my local port 53475, right? I guess outbound connections pick a random port and make sure it isn't in use or something? I assume there is a nice POSIX system call for this sort of thing? get_an_unused_user_port() sort of thing?

Thanks for the info.

2 years ago

in Security: How Network Ports Work on dmiessler.com | grep understanding
I've often wondered about ports used to send data.

I know that a webserver listening on the default HTTP port of 80 will "lock" that port on a machine. Two processes can't listen on the same port (at least with any OS's I'm familiar with).

But when I'm on my desktop, does my browser use a port to send/receive data from a webserver?

If I'm running a local webserver listening on port 80, and then on the same machine I use my browser ... how does the response traffic not go to my webserver (thus confusing everyone involved)?

/boggle

2 years ago

in Security: How Network Ports Work on danielmiessler.com | grep understanding
I've often wondered about ports used to send data.

I know that a webserver listening on the default HTTP port of 80 will "lock" that port on a machine. Two processes can't listen on the same port (at least with any OS's I'm familiar with).

But when I'm on my desktop, does my browser use a port to send/receive data from a webserver?

If I'm running a local webserver listening on port 80, and then on the same machine I use my browser ... how does the response traffic not go to my webserver (thus confusing everyone involved)?

/boggle
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