[c-nsp] SMTP Redirection

[a. rahman isnaini r. sutan]

This could be done if the smtp server directly connected to the router.
Anyway thanks for the link, that's inspired me more.


:: a. rahman isnaini r. sutan



----- Original Message ----- 
From: "Julio Arruda" <jarruda-cnsp at jarruda.com>
To: "Cisco NSP Puck Nether Net" <cisco-nsp at puck.nether.net>
Sent: Sunday, August 19, 2007 1:50 AM
Subject: Re: [c-nsp] SMTP Redirection


:
: The packets from the SMTP client -> to the SMTP server, would not be
: translated by only using the PBR (match ip address 100, set ip next-hop
: 192.168.20.20) piece.
: I noticed that further down his email, Jorge mention a link to:
: http://www.init7.net/anti-spam/
:
: This site explain the configuration of the router AND the configuration
: of the 'intercept' STMP server a little further down the page, BOTH need
: to be done or this would not work.
:
: If you can't do the 'destination IP' NAT on the SMTP server, you should
: be able to do it on the router itself, but this is not covered in the
: link mentioned by Jorge.
:
:
: a. rahman isnaini r. sutan wrote:
: > "layer3 header information is not being changed" > right !.
: > DNAT on the current gateway ?
: >
: > :: a. rahman isnaini r. sutan
: >
: >
: >
: > ----- Original Message ----- 
: > From: "Julio Arruda" <jarruda-cnsp at jarruda.com>
: > To: <cisco-nsp at puck.nether.net>
: > Sent: Saturday, August 18, 2007 7:12 AM
: > Subject: Re: [c-nsp] SMTP Redirection
: >
: >
: > :
: > : The traffic is being routed to the next-hop, but I would assume the
: > : layer3 header information is not being changed, so, the traffic is
: > : arriving at 192.168.20.20 would still have 'destination IP == original
: > : smtp server. you would need to DNAT the traffic somewhere so the IP
: > : stack in the 'intercept' server would see the traffic.
: > :
: > : a. rahman isnaini r. sutan wrote:
: > : > Hallo Jorge,
: > : >
: > : > I did, as the next hop is only ip not with the specific port.
: > : > Any destination to smtp will be redirected to 192.168.20.20 which in
: > this
: > : > config should be directly connected to to gateway (router), while in
: > many
: > : > providers their smtp oftenly covered by firewall which might be 3-4 
hops
: > : > away from this gateway.
: > : > Mail sending is stuck somewhere and I believe the router redirects 
the
: > : > traffic (let say smtp server directly connected) to the server 
without
: > : > having any idea to which opened / specific tcp port.
: > : >
: > : >
: > : > :: a. rahman isnaini r. sutan
: > : >
: > : >
: > : >
: > : > ----- Original Message ----- 
: > : > From: "Jorge Evangelista" <netsecuredata at gmail.com>
: > : > To: <cisco-nsp at puck.nether.net>
: > : > Sent: Saturday, August 18, 2007 4:50 AM
: > : > Subject: Re: [c-nsp] SMTP Redirection
: > : >
: > : >
: > : > :I have not tried it yet, but I think that you could try something 
like
: > that
: > : > :
: > : > : Customers=192.168.10.0/24
: > : > : SmtpRelay=192.168.20.20
: > : > :
: > : > :
: > : > : !
: > : > : access-list 100 remark SMTP Redirect of Customers to
: > smtp.providername.com
: > : > : access-list 100 permit tcp 192.168.10.0 0.0.0.255 any eq smtp
: > : > : !
: > : > : route-map SMTP-Redirect permit 10
: > : > : match ip address 100
: > : > :  set ip next-hop 192.168.20.20
: > : > : !
: > : > : interface FastEthernet 0/0
: > : > : description connected to Internet
: > : > : ip policy route-map SMTP-Redirect
: > : > : !
: > : > : !
: > : > :
: > : > :
: > : > :
: > : > :
: > : > : http://www.init7.net/anti-spam/
: > : > :
: > : > :
: > : > :
: > : > : On 8/17/07, a. rahman isnaini r. sutan <risnaini at speed.net.id> 
wrote:
: > : > : > ip nat outside source static tcp o.o.o.o 25 xxx.xxx.xxx.xxx 
(mail
: > : > server)
: > : > : > 25?
: > : > : > :: a. rahman isnaini r. sutan
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9:48 AM
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