Re: netcat as both client and server and communicating both ways

[Pavel Zhukov <pzhukov () redhat com>]

On Wed, Aug 9, 2017 at 12:07 AM, Blaise R. <rex2k8 () gmail com> wrote:

> I originally asked Fyodor about this via email and he directed me here. I
> think my first email got lost in spam filter because I sent it before I was
> on the list.
>
> Here is the original email:
>
> Hello.
>
> I have a problem with the nmap's ncat, the latest one on Fedora 25, I it
> was 7.40.
> I also compiled 7.50 from sources but the results are all the same.
>
> I realize that I can get echo in many different better ways, this is just
> a distilled down example of a bigger thing I'm attempting to do.
>
> Basically, I use as the server: nc -kl 1234 -c cat
> and as the client: echo 'w' | nc localhost 1234
> It doesn't output the w back to me.
>
> I have tried a server with nc that just reads the input and echos back an
> HTTP header and content and it worked when using a web browser as a client.
>
> I have also tried running just: nc localhost 1234
> And I'm able to interactively enter lines and get them back.
>
> There is also a service called seashells.io, doing: echo 'w' | nc
> seashells.io 1337
> also works and this is the behavior I'd want to achieve.
>
> It looks like some sort of issue when there is nmap's ncat on both client
> and server.
>
> I'd appreciate any response (known bug, won't fix, will fix, patches or
> deeper research welcome, etc.) at all.
​Hello,
There's bug opened in Red Hat bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=1064511​

​It contains link to debian bug and iirc this issue was discussed few times
here.​


> Best regards.
>
> _______________________________________________
> Sent through the dev mailing list
> https://nmap.org/mailman/listinfo/dev
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-- 
Pavel Zhukov
Software Engineer
IRC: landgraf

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