[c-nsp] SMTP Redirection

[Arie Vayner]

Using SLB, the idea is to "catch" the SMTP session, and redirect it to
the actual server you want it to hit.

a very simple example (I could not verify it on a router now, so
syntax might be wrong):

ip slb serverfarm my-smpt
  nat server
  no nat client
  real 1.1.1.1
    inservice
  real 1.1.1.2
    inservice

ip slb virtual smtp
  serverfarm my-smpt
  virtual 0.0.0.0 0.0.0.0 tcp 25
  inservice

The result of this config should catch all TCP port 25 traffic, and
send it to the real servers 1.1.1.1 and 1.1.1.2 while load balancing
between them.
There are some other things that have to be taken care of like
limiting who are the affected clients (if relevant), add probes to
make sure the real servers are up etc.

For more info:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt1/1cfsflb.htm

Arie
On 6/30/06, Paul Stewart <pstewart at nexicomgroup.net> wrote:
> We've looked at SLB for other applications but I'm not sure how it would
> tie into redirecting SMTP?  Can you explain in brief what you have in
> mind?
>
> Thanks again,
>
> Paul
>
>
> -----Original Message-----
> From: Joshua Lauer [mailto:jslauer at hotmail.com]
> Sent: Friday, June 30, 2006 4:48 PM
> To: Paul Stewart; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] SMTP Redirection
>
> have you looked into SLB (server load balancing) works great for SMTP.
>
> Josh
>
> Joshua Lauer
>
> CCIE#16024
> CCNP, CCDP, CCSP, CCIP, RHCE, INFOSEC
>
> ----- Original Message -----
> From: "Paul Stewart" <pstewart at nexicomgroup.net>
> To: <cisco-nsp at puck.nether.net>
> Sent: Friday, June 30, 2006 2:16 PM
> Subject: [c-nsp] SMTP Redirection
>
>
> > Hi there..
> >
> > I've been trying to find a way using Cisco IOS to
> > forcefully redirect
> > SMTP traffic to a specified source.  So we have
> > 1000 users at a remote
> > site for example and some want to use specific
> > SMTP servers for sending
> > out mail but we want to force their SMTP traffic
> > to our mail server ...
> > Just an example...
> >
> > Anything creative that can do this in IOS?
> >
> > Thanks,
> >
> > Paul Stewart
> > Network Administrator
> > Nexicom Inc.
> > http://www.nexicom.net/
> >
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>
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