Trouble IPSec Packet Filter and Mailserver

  • Thread starter Thread starter Markus Mühlich
  • Start date Start date
M

Markus Mühlich

Hi,

I would like to secure my Win2000 Server (SP4) with IPSec Packet
Filter. Therefore I added following filters:

1. Inbound - all Ports - all Protocolls - deny
2. Inbound - Port 25 - TCP - permit
3. Inbound - Port 53 - UDP - permit
4. Inbound - Port 53 - TCP - permit
5. Inbound - Port 110 - TCP - permit

Until now, I did not set any filter for outgoing traffic.

With the a.m. filters MDaemon (6.8.0) cannot resolve any MX/A record
from the DNS Servers (all answers blocked through IPSec). If I change
filter#3 from Port53 (UDP) to any port, MDaemon gets the resolved DNS
records and everything works fine.

But for security reasons I would like to limit the inbound traffic to
the absolut minimun of Ports. What UDP port for inbound traffic (DNS
resolution) I have to use?



Thanks in advance
Markus
 
Create an entry in the permit rule filter to allow traffic to your dns
servers. Traffic for dns name resolution normally uses port 53 udp
[sometimes 53 tcp depending on packet size] "to" the dns server. --- Steve
 
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