Re: Is it true that All communication between front-end and back-end servers goes through TCP port 80?

Tech-Archive recommends: Speed Up your PC by fixing your registry

From: Jeff L (newsgroupsremoveandunderscore_jeff_at_availabletech.net)
Date: 06/04/04 

Date: Fri, 4 Jun 2004 09:41:16 -0400

????????????! Pavel,

I think what is happening, and I am not speaking from experience but only
from the article snip you provided, is that inter-server proxy communication
is being fulfilled through port 80.

I would understand from the article, that it is NOT just strait POP3, IMAP4,
OMA or Active Sync protocol requests forwarded to port 80. I would assume
that the front end server is interpreting the request and making a proxy
call for the information using native commands over port 80.

That type of configuration would allow geographically separate exchange
servers to communicate over the Internet.

Again this is just my interpretation. Perhaps someone from MS will confirm
this.

Perhaps this diagram will help:

Client X POP3 Port 110==> POP3 Port 110 Exchange Front End
                                                    ||
            (Looking for User X mail on backend)
                                                    ||
       Exchange Front End Port 80 ==> Hey got User X Mail? ==> Port 80
Exchange Backend

||

(Exchange Front End needs

User X Mail)

||
      Exchange Front End Port 80 <== Here is User X Mail <== Port 80
Exchange Backend
                                                    ||
                                   (Got Mail for User X)
                                                    ||
Client X POP3 Port 110<== POP3 Port 110 Exchange Front End

?????????,
Jeff Loucks
       Available Technology ®
            Solutions For Professionals ®
                  www.availabletechnology.com

"Pavel Nagaev" <p8p@yandex.ru_REMOVE_IT> wrote in message
news:u6BlcmhSEHA.3872@TK2MSFTNGP10.phx.gbl...
> I beg a pardon, but my example of SMTP is unsuccessful. I mean POP3 and
> IMAP4. Why front-end server proxies them to TCP/80? What is my mistake in
> understanding?
>
> "Jeff L" <newsgroupsremoveandunderscore_jeff@availabletech.net> wrote in
> message news:e7yxNchSEHA.3012@tk2msftngp13.phx.gbl...
> > Pavel,
> >
> > The article does read that front end to back end communication is done
> > through port 80. This is regardless of how the client is connected to
the
> > front end server. It does not specifically address SMTP. I would
consider
> > SMTP communications between two mail servers to be different than proxy
> > requests from clients.
> >
> > I am not sure though and can understand your question.
> >
> > Good Luck,
> > Jeff Loucks
> > Available Technology ®
> > Solutions For Professionals ®
> > www.availabletechnology.com
> >
> >
> >
> > "Pavel Nagaev" <p8p@yandex.ru_REMOVE_IT> wrote in message
> > news:OM$3rKgSEHA.3580@TK2MSFTNGP09.phx.gbl...
> > Hi people,
> >
> > In Exchange Server 2003 Deployment guide, page 127 I found the words:
> >
> > To configure a clustered back-end server, you must map each front-end
> server
> > to the nodes of your cluster, so that either node can accept proxy
> requests
> > from any front-end server in your organization. Proxy requests are
> requests
> > for messaging services from client computers running Microsoft OutlookR
> Web
> > Access, Outlook Mobile Access, Microsoft Exchange ActiveSyncR, POP3, or
> > IMAP4. These proxy requests are sent to the cluster through the
front-end
> > servers. All communication between front-end and back-end servers goes
> > through TCP port 80, regardless of the port used for communication
between
> > the client and front-end server.
> >
> > Is it true that All communication between front-end and back-end
servers
> > goes through TCP port 80?
> >
> > I thought that front-end proxies the requests to corresponding port.
> >
> > POP3(TCP/110)->Front-end->POP3(TCP/110)->Back-end
> > SMTP(TCP/25)->Front-end->SMTP(TCP/25)->Back-end
> > HTTP(TCP/80)->Front-end->HTTP(TCP/80)->Back-end
> >
> > Does it mean that if I connect with POP3 client to front-end server it
> > proxies POP3(TCP 110) packets to back-end server by TCP 80 ? But POP3
> server
> > on back-end server is listening 110 port.
> >
> > I don't understand where I made mistake while reading.
> >
> > --
> > Best Regards
> > Pavel Nagaev
> > Messaging administrator
> > Novorossiysk, Russia
> > Mobile phone: (8617) 65 09 01
> > Office phone: (8617) 64 25 53 ext. 74046
> > Fax: (095) 7975990 ext. 5848
> >
> >
> >
> >
>
>

Relevant Pages

  • RE: Setting up a Proxy Server..
    ... Setting up a Proxy Server.. ... does, this works pretty well, and since workstation thinks it already got ... Since the internet requests from all the machines ...
    (Security-Basics)
  • Re: Proxy VS Firewall
    ... A proxy intercepts packets and processes them on the application layer. ... Microsoft calling their product Proxy server, and just because it caches does ... however there is no such thing as a packet filter to verify that the ... It intercepts all requests to the real server to see if it ...
    (comp.security.firewalls)
  • Re: apache being hit
    ... This would mean the requests are made, ... you should worry if your access log shows: ... to use your server as a proxy. ...
    (Debian-User)
  • Is it posssible to configue ISA 2000 to forward client request to an upstream SOCKS proxy?
    ... We have an ISA 2000 server running on Win 2000 ... SOCKS proxy (to be precise, a SOCKS 4a proxy also running on the same Win ... I have looked at the routing rules to configure ISA to "Redirect requests to ...
    (microsoft.public.isa)
  • Re: ISA Server Problems, please help
    ... Based on the rules you have listed, SecureNAT clients should only be allowed ... The All access rule for SBS Internet Users ... Web Proxy and/or Firewall Client ... > header to the publishing server instead of the actual one. ...
    (microsoft.public.windows.server.sbs)