Changing ttl of incoming packets

[GiZmen]

Hello,
 
Is there any way to change ttl of incoming packet to a lower value ?
I had tried min-ttl option in pf packet filter but this option only increase
ttl to a given value when ttl is lower than this value.
 
I have searched on google and mailing lists but i do not find any answer.
I am running Freebsd 5.2.1 and i am using pf as my packet filter.
 
Thanks for any tips

-- 
Best Regards:
		GiZmen

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