Okay thank you, is there any plans to support this extension in the future?
On Thu, Jun 16, 2022 at 8:20 PM Kerin Millar <kfm@xxxxxxxxxxxxx> wrote:
>
> On Thu, 16 Jun 2022 10:15:55 +0100
> Gmail Support <testingforadept@xxxxxxxxx> wrote:
>
> > Hello,
> >
> > We recently migrated our servers from RedHat to Ubuntu based systems.
> > We used to have an IPtables rule that was blocking packets matching a
> > specific application file and below was the rule we had deployed.
> >
> > -A INPUT -p udp -m udp --dport 514 -m string --string
> > "someapplication.exe" --algo bm -j DROP
> >
> > In NFtables, I read in the blogs that string based blocking is not
> > possible. In the man page of Ubuntu, I see a note "The string type
> > is used to for character strings. A string begins with an
> > alphabetic character (a-zA-Z) followed by zero or more alphanumeric
> > characters or the characters /, -, _ and .. In addition anything
> > enclosed in double quotes (") is recognized as a string."
> >
> > Can you please confirm if string based blocking is supported in Nftables.
>
> There is no equivalent to the string extension in nftables. While it is possible to match against a portion of the packet's payload using a raw payload expression, doing so requires that the offset and length of the data be specified. That is, it cannot search for a pattern and, thus, match at any potential offset.
>
> --
> Kerin Millar
