10-17-2013 05:30 PM - edited 03-11-2019 07:53 PM
Hi,
I'm having an issue trying to open port 25 on our cisco ASA 5510 version 9.1 (2). When a wire tap is placed on the outside port between the ASA and the internet we are getting hits on wireshark, when a port 25 trace from http://www.yougetsignal.com/tools/open-ports is run. No hits or activity is showing up on the debug log using ASDM, even when filtering is applied.
Problem is we cannot open port 25 traffic from the outside network to the inside network so that smtp mail can flow to the Exchange server *.102. Mail can go from the inside network to the ouside network and out to the internet no problems (internal being the most trusted obviously).
Please find attatched the config for the ASA. I have replaced the companyname/domain with "ourcompanyname", our public IP to "ourpublicIP", our ISP to OurISP and our internal IP's with *.*.*.* for sanitisation reasons.
Any help would be greatly appreciated.
Cheers
10-18-2013 02:28 AM
Hi,
Did you try packet-tracer ?
Regards
Mariusz
03-29-2014 02:00 AM
Nick..... there are 3 aspects to this config:
1 Access-l from external to your public IP addr for smtp
2 Access-l from your public IP addr to your internal mail server address
3 NAT rule on the internal mail IP address object.
eg.
access-list outside_access_in extended permit tcp (any or external ip addr object) object external_ip eq smtp
access-list inside_access_in extended permit tcp (any or external ip addr object) object internal_ip eq smtp
object network internal_ip
nat (inside,outside) static external_ip service tcp smtp smtp
03-30-2014 08:06 AM
In the object service for SMTP the source port was defined as 25. The destination port will be 25 but the source will be a random number from the client.
Try this:
no access-list outside_access_in extended permit object smtp any interface outside
access-list outside_access_in extended permit tcp any host "SMTP server IP" eq 25
03-30-2014 05:41 PM
Hello,
So here is what's needed to make this happen and has not been said before
no access-list outside_access_in extended permit object smtp any interface outside
access-list outside_access_in extended permit tcp any host mail.ourcompany.com_ip_address eq 25
Then
object service smtp
no service tcp source eq smtp destination eq smtp
service tcp source eq 25
That's all you need to be able to open and map that port :)
Regards,
Jcarvaja
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