Hi Kings,

This does not work as expected - I know that. To make it work try this:
match start l3-start offset 36 size 2 string jo

The problem with 'payload-start" is that it does not start from where the
payload is or the FPM looks differently at the packet :)

The above should work. The 36 bytes are:
20 - IP Header
8 - ICMP Header
8 - junk data in ICMP payload

Also make sure that the ICMP packet is at least of 42 bytes in length to be
properly parsed by FPM.

btw: I assume you use "data 6A6F" parameter when pinging :)

Regards,
Piotr


2010/11/18 Kingsley Charles <[email protected]>

> Hi all
>
> The following doesn't match.
>
> match start ICMP payload-start offset 0 size 2 string "jo"
>
> The following is matched from 14 bytes onwards
>
> match start ICMP payload-start offset 0 size 14 string "jo"
>
>
> "jo" is 2 bytes in length and hence I thought putting 2 bytes would be
> suffice starting from ICMP payload.
>
>
> Even if I consider 8 bytes of ICMP header, how come it requires 14 byes?
>
> *start ICMP payload-start *means it should start from the ICMP payload
> which means 2 bytes is correct right?
>
>
>
>
> With regards
> Kings
>
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