There is an application which is trying to talk to a host on a particular port and I want to see if that port is getting blocked .. I have the wireshark captures but unable to find out which error to look for.
Can you please advice ?
asked 05 Aug '16, 04:52
edited 05 Aug '16, 07:09
Depending on the security appliances on the remote site (firewall, proxy server, switch/router ACL's, etc) you will see one of the following symptoms in the 3-way handshake:
1) TCP SYN packets going out, but no TCP SYN ACK replies
2) TCP SYN packets going out, but with a TCP SYN RST reply
Item 1) above could also be due to an inability to find a return route as well, thus not just symptomatic of a blocked port.
answered 13 Aug '16, 22:04