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

Pavel,

That bug is a different issue that was resolved when we added the
--no-shutdown option. That issue is with Ncat in client/connect mode, and
Blaise is describing a problem with Ncat in server/listen mode.

Dan

On Wed, Aug 9, 2017 at 12:46 AM, Pavel Zhukov <[email protected]> wrote:

> On Wed, Aug 9, 2017 at 12:07 AM, Blaise R. <[email protected]> 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
>> Archived at http://seclists.org/nmap-dev/
>>
>
>
>
> --
> Pavel Zhukov
> Software Engineer
> IRC: landgraf
>
>
>
> _______________________________________________
> Sent through the dev mailing list
> https://nmap.org/mailman/listinfo/dev
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>

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