Solved

Access-list smtp

Posted on 2009-05-04
11
728 Views
Last Modified: 2013-11-30
When I apply this acl to the external interface connected to the internet it breaks all traffic.

int ser 0/0/0
ip access-group 101 in

Any ideas?
Extended IP access list 101
    10 permit tcp 0.0.0.0 0.0.3.255 0.0.0.0 0.0.0.3 eq smtp
    20 permit tcp 0.0.0.0 0.0.7.255 0.0.0.0 0.0.0.3 eq smtp
    30 deny tcp any any eq smtp

Open in new window

0
Comment
Question by:kitbarr
  • 6
  • 4
11 Comments
 
LVL 8

Expert Comment

by:akalbfell
ID: 24296580
what are you trying to do? use the access list to only permit SMTP traffic or you want http/https traffic to pass through also?
0
 
LVL 43

Expert Comment

by:JFrederick29
ID: 24296739
Add permit ip any any at the bottom since there is any implicit "deny all" at the end.

permit tcp 0.0.0.0 0.0.3.255 0.0.0.0 0.0.0.3 eq smtp
permit tcp 0.0.0.0 0.0.7.255 0.0.0.0 0.0.0.3 eq smtp
deny tcp any any eq smtp
permit ip any any
0
 

Author Comment

by:kitbarr
ID: 24298058
adding permit ip any any allows traffic to flow however the deny tcp any any eq smtp seems to be catching all smtp traffic. the first two lines don't seem to be working.
0
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 
LVL 8

Expert Comment

by:akalbfell
ID: 24298125
what are you trying to do?
permit SMTP traffic from one host out to the internet but block any SMTP traffic from coming out from another machine?

0
 

Author Comment

by:kitbarr
ID: 24298159
I want to allow all smtp traffic out however only allow smtp traffic in from mx logic. 208.65.144.0/21 and 208.81.64.0/22 is what I am trying to allow in.
0
 

Author Comment

by:kitbarr
ID: 24298168
Yes and I would also like to allow all other http traffic. I'm only trying to block smtp from the outside in.
0
 

Author Comment

by:kitbarr
ID: 24298187
This is what it looks like right now
GWAQUA(config-ext-nacl)#do sh access-list
Extended IP access list 102
    40 permit ip any any (600928 matches)

Open in new window

0
 
LVL 8

Accepted Solution

by:
akalbfell earned 500 total points
ID: 24298261
gotcha...

permit tcp 208.81.64.0 0.0.3.255 any eq smtp
permit tcp 208.65.144.0 0.0.7.255 any eq smtp
deny tcp any any eq smtp
permit ip any any

applied to the outside interface coming in

0
 

Author Comment

by:kitbarr
ID: 24298526
That worked perfectly. What is the difference between
access-list 101 permit tcp 0.0.0.0 0.0.3.255 eq smtp any eq smtp and
access-list 101 permit tcp 208.65.144.0 0.0.3.255 any eq smtp
0
 

Author Closing Comment

by:kitbarr
ID: 31577607
This person kept right on at answering my questions as we went. Solved my problem and also helped me understand a little bit more.
0
 
LVL 8

Expert Comment

by:akalbfell
ID: 24298665
permit tcp 0.0.0.0 0.0.3.255 0.0.0.0 0.0.0.3 eq smtp
that is saying permit traffic from any host in the 255.255.252.0 subnet going to any host in the 255.255.255.252 subnet

access-list 101 permit tcp 208.65.144.0 0.0.3.255 any eq smtp
this is more specifically saying permit from the 208.65.144.0/22 network to any host in your network

Glad to help!

0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
Shadow IT is coming out of the shadows as more businesses are choosing cloud-based applications. It is now a multi-cloud world for most organizations. Simultaneously, most businesses have yet to consolidate with one cloud provider or define an offic…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question