[c-nsp] SMTP Redirection

[Joshua Lauer]

SLB is like an advanced version of NAT rotary, but 
since you use SLB already then you already know that 
:)

Basically you would have an SMTP "farm" and a 
vserver address that you have everyone use as the 
SMTP server IP address. Piece of cake...We use SLB 
with SMTP at my location, we have about 20 servers 
in a farm and....by using the NAT functionality of 
SLB the servers dont even need to be on the same 
subnet.


jl


Joshua Lauer

CCIE#16024
CCNP, CCDP, CCSP, CCIP, RHCE, INFOSEC

----- Original Message ----- 
From: "Arie Vayner" <ariev at vayner.net>
To: "Paul Stewart" <pstewart at nexicomgroup.net>
Cc: "Joshua Lauer" <jslauer at hotmail.com>; 
<cisco-nsp at puck.nether.net>
Sent: Saturday, July 01, 2006 3:13 PM
Subject: Re: [c-nsp] SMTP Redirection


> 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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