[colug-432] nc replacement in RHEL7?

[Rick Hornsby]

> On May 28, 2015, at 15:44, Jeff Frontz <jeff.frontz at gmail.com> wrote:
> 
> I'm not quite sure what -z does (does it actually do a connect or just some subset of the TCP connection setup?),

Yep. -z is a TCP half-open.  Sends SYN, waits for SYNACK and then quits.  Makes it super easy (and scriptable) to test basic connectivity and catch firewall, service not running etc issues.

It is a much better version of what I often hear referred to as the "telnet test"

> but is "traceroute -T -p 80 some host" roughly equivalent?

Good thought but it does not appear so.  That command is successful regardless of which port I try, including ones known not to be listening.  It should fail with connection refused or at least exit non-zero. I'm not really sure what the port flag is doing - sending some kind of an ICMP echo message to that port?


> 



> 
> 
>> On Thu, May 28, 2015 at 3:53 PM, Rick Hornsby <richardjhornsby at gmail.com> wrote:
>> 
>>    nc -zv somehost 80
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