Use netcat to check udp port status
Damn you, Windows. You’ve conditioned me to use telnet for network connectivity checks instead of superior tools like netcat (which supports UDP ports).
I nearly forgot this one so I thought I’d write it down:
nc -vzu <ip address> <udp port or port range>
- -v enables verbose mode for easier feedback.
- -z scans for listening daemons without sending any data to them.
- -u uses UDP instead of TCP.
‘Nuff said.
How To Search Info Column In WireShark
This one has bugged me for awhile now. On occasion, I’ll want to search the info column section of a packet capture for a specific string (e.g. server name, email address, web site url, etc). As it turns out, it’s really simple to do in WireShark:
Open Edit→Find Packet. Under Find select String and under Search In select Packet list.
Fun With Path MTU Discovery
This is an old post from my previous blog but I came across a similar issue fairly recently so I thought I’d resurrect it (lucky you eh?). The topic pertains to a networking process known as “Path MTU Discovery” and the data transmission issues that can involve it.
