This is a static archive of our old Q&A Site. Please post any new questions and answers at ask.wireshark.org.

traffic to closed ports

0

A dumb question to understand how Wireshark works: if I monitor my inbound traffic and someone send me a packet directed to a closed port, will I see this packet in wireshark?

asked 29 Oct '15, 10:32

rok's gravatar image

rok
26446
accept rate: 0%


One Answer:

0

Yes, unless you have a local firewall running that blocks the packet before Wireshark can record it. But without, a closed port will result in an reset packet, which you should see.

answered 29 Oct '15, 10:36

Jasper's gravatar image

Jasper ♦♦
23.8k551284
accept rate: 18%

could you tell me more about the reset packet? Is it the reply I send once I receive a packet directed to my closed port? I mean, if you send me a tcp packet directed to my ip:port where port is closed.. I will see it normally in wireshark, and you'll get a reset packet as response.. am I right? Thank you

(29 Oct '15, 10:41) rok
1

Yes, if a packet arrives for a closed port your TCP stack will reply with an reset packet. You should see both in Wireshark.

(29 Oct '15, 10:43) Jasper ♦♦