[Last Call] Learn how to a build a cloud-first strategyRegister Now

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 982
  • Last Modified:

HTTP 1.1 Protocol Compliance - RFC 2616

I am connecting to an web server via an F5.  The F5 has HTTP protocol enforcement enabled and I am encountering a strange problem.

However, the CRUX of my question is:

Can a Web Server send more than one "HTTP/1.1 100 Continue" response codes to a client is the following scenario:

1.  Client Connects to Web Server
2.  Client SENDS POST HEADER
  
    POST /site/service HTTP/1.1
    User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; MS Web Services Client Protocol 2.0.50727.3615)
    Authorization: Basic b52gstehdy7637=
    Content-Type: text/xml; charset=utf-8
    SOAPAction: "helloMessage"
    Host: akl34svr.internal
    Content-Length: 1008
    Expect: 100-continue

Open in new window

3.  Server Sends:
HTTP/1.1 100 Continue

Open in new window

4.  Server Sends:
HTTP/1.1 100 Continue

Open in new window

5.  Client Sends "POST REQUEST"
6.  Server Sends:
HTTP/1.1 200 OK

Open in new window

7.  Server Sends: "Response Header"
8.  Server Sends: "Response Body"
9.  Connection Closes

(With the exception of 1 and 9 - every numbered entry reflects a unique TCP packet on the wire)

For some reason this server is ALWAYS sending two HTTP/1.1 100 Continue responses immediately after it receives the POST Header.  I have tried some other servers and they only send one "HTTP/1.1 100 Continue".  So I want to know if this is RFC Compliant.

Additionally I have also tried not waiting for the "HTTP/1.1 100 Continue" and just sending my "POST REQUEST" immediately.  This results in the duplicate "HTTP/1.1 100 Continue"s arriving between packet 5 and packet 6.

As reference (and this is not the question) the F5 barfs when the "HTTP/1.1 100 Continue" packets arrive within 1ms of each other.  If they arrive within > ~200ms the F5 just accepts the traffic.  It is only when they are arriving within 1ms of each other that the F5 drops the connection.  The reason they can sometimes arrive within 1ms is because of Nagles Algorithm queuing the two outbound packets and suddenly sending them in a burst.

So just to recap the question is:

Is it RFC compliant for the server to send multiple "HTTP/1.1 100 Continue" response codes?

Thanks.

-Rowan
0
rowansmith
Asked:
rowansmith
1 Solution
 
Dave BaldwinFixer of ProblemsCommented:
Here you go: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html  The answer is: "A client MUST be prepared to accept one or more 1xx status responses prior to a regular response"
0

Featured Post

Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now