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I'm trying to learn some about HTML, so any help you can give me would be
greatly appreciated.

Do all requests and responses require an HTTP header to get through most
firewalls as valid HTTP traffic or can headers be omitted once the
connection is established as long as the client and server know how to
interpret the data?

Is it possible to pass binary over HTTP without converting it to ASCII?

Will firewalls block this type of data?

"Jim Hubbard" <> wrote
>
> I'm trying to learn some about HTML, so any help you can give me would be
> greatly appreciated.
>
> Do all requests and responses require an HTTP header to get through most
> firewalls as valid HTTP traffic or can headers be omitted once the
> connection is established as long as the client and server know how to
> interpret the data?

This is (respectfully) a meaningless question. There is no "connection" in
the sense of, say, an FTP connection. HTTP is stateless and asynchronous.
The client issues a request, that request is serviced by the server and that
is the end of the matter. The TCP/IP connection is broken. No further
interaction. End of conversation.

> Is it possible to pass binary over HTTP without converting it to ASCII?

Yes. A jpeg is binary data.

> Will firewalls block this type of data?

Firewalls block what you tell them to and usually by port address. I doubt
if a firewall will delve into the data to see if it needs blocking.

--
Cheers
Richard.

"rf" <rf@.invalid> wrote in message
news:EkrDd.107881$...
> "Jim Hubbard" <> wrote
>>
>> I'm trying to learn some about HTML, so any help you can give me would be
>> greatly appreciated.
>>
>> Do all requests and responses require an HTTP header to get through most
>> firewalls as valid HTTP traffic or can headers be omitted once the
>> connection is established as long as the client and server know how to
>> interpret the data?
>
> This is (respectfully) a meaningless question. There is no "connection" in
> the sense of, say, an FTP connection. HTTP is stateless and asynchronous.
> The client issues a request, that request is serviced by the server and
> that
> is the end of the matter. The TCP/IP connection is broken. No further
> interaction. End of conversation.

I must (also respectfully) disagree. The RFC2616
(ftp://ftp.isi.edu/in-notes/rfc2616.txt) dealing with HTTP protocol defines
"Persistent Connections" that are kept open starting with version 1.1 of the
HTTP Protocol. You would, however, be correct when referring to the HTTP
1.0 specification.

>
>> Is it possible to pass binary over HTTP without converting it to ASCII?
>
> Yes. A jpeg is binary data.

But is it converted to ASCII for the transfer and back from ASCII on the
recieving side?

>
>> Will firewalls block this type of data?
>
> Firewalls block what you tell them to and usually by port address. I doubt
> if a firewall will delve into the data to see if it needs blocking.

Also not quite correct (see
http://www.cert.org/security-improve...ces/p058.html).

A firewall CAN block any packet type based on a number of criteria.

What I am after is learning how the packets are formed that pass binary data
(if possible) over HTTP in such a way that they look like regular, permitted
HTTP traffic. And, can binary data be passed through instead of ASCII
converted data?

Examples of the headers and binary data packet headers would be most
helpful.

Thanks for your input.

Jim

"Jim Hubbard" <> wrote
> "rf" <rf@.invalid> wrote in message

> > The client issues a request, that request is serviced by the server and
> > that
> > is the end of the matter. The TCP/IP connection is broken. No further
> > interaction. End of conversation.
>
> I must (also respectfully) disagree. The RFC2616
> >
> >> Is it possible to pass binary over HTTP without converting it to ASCII?
> >
> > Yes. A jpeg is binary data.
>
> But is it converted to ASCII for the transfer and back from ASCII on the
> recieving side?

> >> Will firewalls block this type of data?
> >
> > Firewalls block what you tell them to and usually by port address. I
doubt
> > if a firewall will delve into the data to see if it needs blocking.
>
> Also not quite correct (see
> http://www.cert.org/security-improve...ces/p058.html).
>

****. Why did you ask the bloody question in the first place?

Just go and refer to the damn RFC's!

--
Cheers
Richard.

Jim Hubbard wrote:
> "rf" <rf@.invalid> wrote in message
> news:EkrDd.107881$...
>
>>"Jim Hubbard" <> wrote
>>
>>>Is it possible to pass binary over HTTP without converting it to ASCII?
>>
>>Yes. A jpeg is binary data.
>
> But is it converted to ASCII for the transfer and back from ASCII on the
> recieving side?

No.

Thanks.


"Leif K-Brooks" <> wrote in message
news:...
> Jim Hubbard wrote:
>> "rf" <rf@.invalid> wrote in message
>> news:EkrDd.107881$...
>>
>>>"Jim Hubbard" <> wrote
>>>
>>>>Is it possible to pass binary over HTTP without converting it to ASCII?
>>>
>>>Yes. A jpeg is binary data.
>>
>> But is it converted to ASCII for the transfer and back from ASCII on the
>> recieving side?
>
> No.

On Fri, 07 Jan 2005 08:00:36 GMT, "rf" <rf@.invalid> wrote:

>"Jim Hubbard" <> wrote
>>
>> I'm trying to learn some about HTML, so any help you can give me would be
>> greatly appreciated.

There is _very_ little HTTP that you need to know to understand web
authoring, or certainly HTML.


>> Do all requests and responses require an HTTP header

Yes. Although this can be very minimal in the limiting case.

I can't really see any benefit to trying to trim down HTTP headers in
particular.

>This is (respectfully) a meaningless question. There is no "connection" in
>the sense of, say, an FTP connection.

Of course there is. For one thing, look at the differences between
HTTP 1.1 and 1.0

> HTTP is stateless and asynchronous.

HTTP has state. It doesn't have _much_ state, and it infamously
doesn't have a notion of application-level state between requests, but
it does have some minimal state at this session level.

>The client issues a request, that request is serviced by the server and that
>is the end of the matter.

>The TCP/IP connection is broken.

The TCP connection will generally be maintained after a HTTP request.
There's no reason why it ought to be broken immediately.

>Firewalls block what you tell them to and usually by port address. I doubt
>if a firewall will delve into the data to see if it needs blocking.

Many sophisticated firewalls "delve" and have done so for some years
now.

On Fri, 7 Jan 2005 02:51:12 -0500 Jim Hubbard wrote:


> I'm trying to learn some about HTML, so any help you can give me would
> be
> greatly appreciated.

> Do all requests and responses require an HTTP header to get through
> most
> firewalls as valid HTTP traffic or can headers be omitted once the
> connection is established as long as the client and server know how to
> interpret the data?

> Is it possible to pass binary over HTTP without converting it to ASCII?

> Will firewalls block this type of data?

You're apparently reading much more than you need to.
As html coding is ascii, there is no need for including headers and all that
other garbage.
Anything else required is handled by the servers.
Write the code, post it, and wait for visitors.

On Fri, 7 Jan 2005 09:50:24 -0600, "Richard" <Anonymous@127.001>
wrote:

>As html coding is ascii,

I used to think you were a freelance idiot, but now you're apparently
challening Dave Winer.

> there is no need for including headers and all that
>other garbage.

It's a question of HTTP, not HTML. But you're a moron, so what can we
expect.