topic Re: Firewalling&__MicrosoftOutlook in Network Security

Firewalling&__MicrosoftOutlook

secureIT — Mon, 11 Mar 2019 13:21:29 GMT

Hi Security team,

Its very strange to say that microsoft outlook is not function because of firewall. Hopefully it should not !! but what happens is - mails are not getting downloaded or sent via outlook express from Local Lan. With the same outlook configuration and when Datacard is being used, it works perfectly.

Attaching the error message and firewall configuration

NB-Public ips configured are not the real ips ..

webmail is working from the local lan& only outlook is not !!!

Pls help !!

regards

Rajesh P

Re: Firewalling&__MicrosoftOutlook

Farrukh Haroon — Mon, 28 Jul 2008 18:16:14 GMT

Where is the email server and clients? (Zone) What are the IPs?

Regards

Farrukh

Re: Firewalling&__MicrosoftOutlook

oldcreek12 — Mon, 28 Jul 2008 20:40:03 GMT

I would turn off smtp inspection before try anything else.

Re: Firewalling&__MicrosoftOutlook

secureIT — Tue, 29 Jul 2008 16:28:02 GMT

Its already turned off

no inspect esmtp

Re: Firewalling&__MicrosoftOutlook

secureIT — Tue, 29 Jul 2008 16:30:21 GMT

Hi,

mail server is outside the firewall (not in this network), its a public server. clients are from Inside (192.168.4.0)

regards

Rajesh P

Re: Firewalling&__MicrosoftOutlook

secureIT — Wed, 30 Jul 2008 04:56:17 GMT

Hi Team -- Can anyone help me out on this please...

regards

Rajesh P

Re: Firewalling&__MicrosoftOutlook

angusr — Wed, 30 Jul 2008 05:38:51 GMT

static (dmz,inside) 10.10.10.10 10.10.10.10 netmask 255.255.255.255

Re: Firewalling&__MicrosoftOutlook

secureIT — Wed, 30 Jul 2008 07:45:17 GMT

The mail server is not in DMZ/Inside. Its a public mail server which is located outside the network.

We can skip thinking of DMZ in this scenario..

Re: Firewalling&__MicrosoftOutlook

angusr — Wed, 30 Jul 2008 12:30:37 GMT

So are you using MS Exchange ports or SMTP/POP3? If Exchange, could ISP be blocking ports? What's the "Datacard" and why does this work when using it? Could you setup VPN with mail server/mail server's network?

Re: Firewalling&__MicrosoftOutlook

secureIT — Fri, 01 Aug 2008 02:20:44 GMT

I have resolved the problem by myself...

I have connected the laptop directly to the modem with the ip address as that of firewall public ip. Then i was able to access mails thru outlook..

This means it needs a public ip..

So, I did a PAT for the entire Local Lan segment. Now outlook is working fine without any problem.

New problem is that, for machines configured as DHCP are not able to receive mails. where are those with static does not have any problem.

Earlier i had configured PAT only for Proxy servers, because, client should access internet thru only proxy.

Anyways my problem is resolved.

Maybe this session will helpful for others...

Thanks to All who participated in this session...

regars

Rajesh P

rajesh.pvk3@gmail.com

Re: Firewalling&__MicrosoftOutlook

Farrukh Haroon — Fri, 01 Aug 2008 02:39:31 GMT

Well OWA would use the proxy server as it is accessed through the web browse, the Outlook client does not use the proxy server (at least by default). You could setup RPC over HTTPS if you want to use the proxy.

DHCP clients will also work, your current NAT statements only allow NAT/PAT for one IP:

access-list 128 extended permit ip host 192.168.4.250 any

Regards

Farrukh

Re: Firewalling&__MicrosoftOutlook

secureIT — Fri, 01 Aug 2008 17:13:10 GMT

Now it is

access-list 128 extended permit ip 192.168.4.0 255.255.255.0 any

But still dhcp configured machines are not receiving the mails properly..

once made to static, it works....

Re: Firewalling&__MicrosoftOutlook

Farrukh Haroon — Fri, 01 Aug 2008 18:49:37 GMT

The DHCP client pool = what?

Regards

Farrukh