what happens to a packet travelling from one network to another?

I had a question from a boss asking how a packet, or lets say a word file
travels from one network over a vpn to another?

I just said it has the destination IP etc and uses the routes on a routes
and our VPN device encypts the data etc, but he was unimpressed, he wanted a
deeper explanation, what should I of said? Can anyone help me explain this
down to the packet/header level, it would be great or a link to a webpage
which eplains this.

This document contains what you need to know.

http://www.microsoft.com/technet/net...n/vpnover.mspx

To summarize, the traffic between the client and the VPN server is
normal network traffic using Ethernet. When the VPN server detects that the
packet need to be delivered through the VPN tunnel to reach its destination
it encrypts the entire packet (including the private IP addresses) and adds
a new header. This header contains the public IP of the destination VPN
server. This packet is then sent through the Internet to the target VPN
server. The VPN server knows what traffic needs to go through the tunnel
because it has a route pointing to the VPN endpoint IP.

When the second VPN server receives the packet it strips off the outer
wrapper (because it has reached its detination). It then decrypts the
payload to recover the original private-addressed packet. It delivers this
packet to the workstation/server it is addressed to using normal Ethernet
LAN delivery methods.

The operation of the VPN tunnel is transparent to the LAN networking.
The LAN machines simply send the traffic across the LAN as it would to any
other router. The VPN router detects data which needs to be tunnelled.

"Gonzo" <(E-Mail Removed)> wrote in message
news:e%(E-Mail Removed)...
>I had a question from a boss asking how a packet, or lets say a word file
>travels from one network over a vpn to another?
>
> I just said it has the destination IP etc and uses the routes on a routes
> and our VPN device encypts the data etc, but he was unimpressed, he wanted
> a deeper explanation, what should I of said? Can anyone help me explain
> this down to the packet/header level, it would be great or a link to a
> webpage which eplains this.
>

So is it the header of the packet that contains the IP for the destination?

In the example is the word doc brocken down to packets?


"Bill Grant" <not.available@online> wrote in message
news:%(E-Mail Removed)...
> This document contains what you need to know.
>
> http://www.microsoft.com/technet/net...n/vpnover.mspx
>
> To summarize, the traffic between the client and the VPN server is
> normal network traffic using Ethernet. When the VPN server detects that
> the packet need to be delivered through the VPN tunnel to reach its
> destination it encrypts the entire packet (including the private IP
> addresses) and adds a new header. This header contains the public IP of
> the destination VPN server. This packet is then sent through the Internet
> to the target VPN server. The VPN server knows what traffic needs to go
> through the tunnel because it has a route pointing to the VPN endpoint IP.
>
> When the second VPN server receives the packet it strips off the outer
> wrapper (because it has reached its detination). It then decrypts the
> payload to recover the original private-addressed packet. It delivers this
> packet to the workstation/server it is addressed to using normal Ethernet
> LAN delivery methods.
>
> The operation of the VPN tunnel is transparent to the LAN networking.
> The LAN machines simply send the traffic across the LAN as it would to
> any other router. The VPN router detects data which needs to be tunnelled.
>
> "Gonzo" <(E-Mail Removed)> wrote in message
> news:e%(E-Mail Removed)...
>>I had a question from a boss asking how a packet, or lets say a word file
>>travels from one network over a vpn to another?
>>
>> I just said it has the destination IP etc and uses the routes on a routes
>> and our VPN device encypts the data etc, but he was unimpressed, he
>> wanted a deeper explanation, what should I of said? Can anyone help me
>> explain this down to the packet/header level, it would be great or a link
>> to a webpage which eplains this.
>>
>
>

All network traffic is broken down into packets.

"Gonzo" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> So is it the header of the packet that contains the IP for the
> destination?
>
> In the example is the word doc brocken down to packets?
>
>
> "Bill Grant" <not.available@online> wrote in message
> news:%(E-Mail Removed)...
>> This document contains what you need to know.
>>
>> http://www.microsoft.com/technet/net...n/vpnover.mspx
>>
>> To summarize, the traffic between the client and the VPN server is
>> normal network traffic using Ethernet. When the VPN server detects that
>> the packet need to be delivered through the VPN tunnel to reach its
>> destination it encrypts the entire packet (including the private IP
>> addresses) and adds a new header. This header contains the public IP of
>> the destination VPN server. This packet is then sent through the Internet
>> to the target VPN server. The VPN server knows what traffic needs to go
>> through the tunnel because it has a route pointing to the VPN endpoint
>> IP.
>>
>> When the second VPN server receives the packet it strips off the outer
>> wrapper (because it has reached its detination). It then decrypts the
>> payload to recover the original private-addressed packet. It delivers
>> this packet to the workstation/server it is addressed to using normal
>> Ethernet LAN delivery methods.
>>
>> The operation of the VPN tunnel is transparent to the LAN networking.
>> The LAN machines simply send the traffic across the LAN as it would to
>> any other router. The VPN router detects data which needs to be
>> tunnelled.
>>
>> "Gonzo" <(E-Mail Removed)> wrote in message
>> news:e%(E-Mail Removed)...
>>>I had a question from a boss asking how a packet, or lets say a word file
>>>travels from one network over a vpn to another?
>>>
>>> I just said it has the destination IP etc and uses the routes on a
>>> routes and our VPN device encypts the data etc, but he was unimpressed,
>>> he wanted a deeper explanation, what should I of said? Can anyone help
>>> me explain this down to the packet/header level, it would be great or a
>>> link to a webpage which eplains this.
>>>
>>
>>
>
>

Yes, the packet header contains both destination and source information.
http://en.wikipedia.org/wiki/IPv4

"Gonzo" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> So is it the header of the packet that contains the IP for the destination?
>
> In the example is the word doc brocken down to packets?
>
>
> "Bill Grant" <not.available@online> wrote in message
> news:%(E-Mail Removed)...
>> This document contains what you need to know.
>>
>> http://www.microsoft.com/technet/net...n/vpnover.mspx
>>
>> To summarize, the traffic between the client and the VPN server is normal
>> network traffic using Ethernet. When the VPN server detects that the packet
>> need to be delivered through the VPN tunnel to reach its destination it
>> encrypts the entire packet (including the private IP addresses) and adds a
>> new header. This header contains the public IP of the destination VPN server.
>> This packet is then sent through the Internet to the target VPN server. The
>> VPN server knows what traffic needs to go through the tunnel because it has a
>> route pointing to the VPN endpoint IP.
>>
>> When the second VPN server receives the packet it strips off the outer
>> wrapper (because it has reached its detination). It then decrypts the payload
>> to recover the original private-addressed packet. It delivers this packet to
>> the workstation/server it is addressed to using normal Ethernet LAN delivery
>> methods.
>>
>> The operation of the VPN tunnel is transparent to the LAN networking. The
>> LAN machines simply send the traffic across the LAN as it would to any other
>> router. The VPN router detects data which needs to be tunnelled.
>>
>> "Gonzo" <(E-Mail Removed)> wrote in message
>> news:e%(E-Mail Removed)...
>>>I had a question from a boss asking how a packet, or lets say a word file
>>>travels from one network over a vpn to another?
>>>
>>> I just said it has the destination IP etc and uses the routes on a routes
>>> and our VPN device encypts the data etc, but he was unimpressed, he wanted a
>>> deeper explanation, what should I of said? Can anyone help me explain this
>>> down to the packet/header level, it would be great or a link to a webpage
>>> which eplains this.
>>>
>>
>>
>
>