Re: Options field in Outer IP Header

["Amey Gokhale" <agokhale@postmaster.co.uk>]

you guessed it right amol, outer IP header doesn;t copy inner IP header's option fields. for him, it is just a normal IP payload which has to be encapsulated, whtever may be the inner header/payload contents. 

but it doesn;t imply tht options are not constructed for outer IP header. if the environment needs every packet to be attached with security options....in tht case outer header will attach it;s own option fields. But option fields of inner IP header will not be copied in outer IP header.
 
any corrections r welcome.
regards,
amey

On Tue, 29 Jan 2002 11:13:15 +0530
 "Amol Deshmukh" <adeshmukh@pace.stpp.soft.net> wrote:
> Hi,
> 
>     This is regarding the Options field in the outer IP Header for IPsec
> Tunnel mode.
>     In RFC2401, section 5.1.2.1 gives the Header construction for Tunnel
> mode. For the Options field, the following line has been printed.
> 
> Header fields    Outer Header                Inner Header
> Options            never copied                 no change
> 
> I have a doubt. Does this mean:
> 1> IPsec never copies the Options field from the inner Header nor
>     does it construct them for the Outer Header ?
> 2> IPsec always attaches an outer IP Header of 20 bytes ?
> 3> It is not the responsibility of IPsec to attach the Options field for the
>     Outer IP header ?
> 
> I would be really thankful if you could help me with this.
> 
> Thanks and Regards,
> Amol.
> 
> 
> 
>