July 24, 2008 07:21pm pdt

1. war1 9,150
2. keith_ala... 4,500
3. MPECSInc 3,500
4. tigermatt 2,800
5. Cyclops3... 2,750
6. noci 2,500
6. darkstar3d 2,500
8. Chris-Dent 2,375
9. Tomun 2,000
9. sjef_bos... 2,000
9. SuprSpy79 2,000
9. BiPod 2,000
9. coolsport00 2,000
9. lamaslany 2,000
9. manu4u 2,000
9. LeeTutor 2,000
9. samccarthy 2,000
9. arnold 2,000
9. fgrushev... 2,000
9. robrandon 2,000
9. grahamno... 2,000
9. shawnleh... 2,000
9. mwecom... 2,000
9. Roachy1... 2,000
9. omarfarid 2,000
9. BSonPosh 2,000
9. plug1 2,000
9. DenverRick 2,000

1. war1 17,150
2. Sembee 10,500
3. keith_ala... 5,100
4. Cyclops3... 4,750
5. MPECSInc 3,500
6. JimboEfx 3,000
6. dalesit 3,000
8. ATIG 2,900
9. tigermatt 2,800
10. darkstar3d 2,500
10. noci 2,500
10. purplepo... 2,500
13. PsiCop 2,450
14. Chris-Dent 2,375
15. Tomun 2,000
15. samccarthy 2,000
15. mwecom... 2,000
15. redseatec... 2,000
15. kbbcnet 2,000
15. robrandon 2,000
15. moorhous... 2,000
15. arnold 2,000
15. SysExpert 2,000
15. LeeTutor 2,000
15. dragon-it 2,000
15. fgrushev... 2,000
15. SuprSpy79 2,000
15. sciwriter 2,000
15. _nn_ 2,000
15. samtran0... 2,000
15. coolsport00 2,000
15. BiPod 2,000
15. DenverRick 2,000
15. lamaslany 2,000
15. plug1 2,000
15. mcse2007 2,000
15. rwaldicott 2,000
15. Burns2007 2,000
15. omarfarid 2,000
15. natoka 2,000
15. BSonPosh 2,000
15. manu4u 2,000
15. predragpe... 2,000
15. FixingStuff 2,000
15. nitadmin 2,000
15. sjef_bos... 2,000
15. grahamno... 2,000
15. redgun 2,000
15. shawnleh... 2,000
15. Roachy1... 2,000

05.05.2008 at 01:59PM PDT, ID: 23377755

	[x] Attachment Details

[x]

The Solution Rating System

With so many solutions, how can you tell which solutions are most likely to help you and which ones are not? To provide you with a tool to use, we rate our solutions based on various elements that most accurately determine if a solution is a quality solution. To explain what factors affect the solution rating, here are the elements we take into consideration when formulating our solution rating.

The Grade of the Solution
The Zone Rank of the Expert Providing the Solution
The Number of Author and Expert Comments
The Number of Experts Contributing
The Feedback of the Community

Your Input Matters
Because of the way the system is set up, the most important variable in this equation is you. As a member of Experts Exchange, you are able to cast your vote on the quality of the solutions in regard to how complete, accurate, helpful and easy to understand each solution is. When you provide your feedback, each rating is adjusted accordingly. So, if you see a solution that has a poor rating that you think is a good solution, let us know by rating it. As you do, the rating will be adjusted and will become more accurate for other members of our site.

If you have any suggestions that you would like to make for our rating system, please ask a question in the Suggestions Zone of Community Support.

Thank you!

8.0

Outgoing pop3 traffic unable to connect to hosted exchange

Zones: Exchange Email Server, Post Office Protocol 3 (POP3)

Tags: Microsoft, Hosted Exchange Server, 2003, Pop3 - port 110

A client of mine uses a hosted exchange 2003 service for email. RPC over http works fine and so does smtp. Pop3, however, will not connect from certain networks using nat.
Testing done with telnet to port 110.
I am the ISP for this client and I do not block any connectivity to/from our upstream providers.
Telnet results to port 110 show a flashing cursor and any input kills the connection and returns to a prompt.
The exchange hosting company provided remote support to the client and tried to telnet to port 110 on their server from inside the clients network and the result was the flashing cursor. They said port 110 was being blocked.

On a different network:
I've tested from a workstation (several) going out a pix501 to a 3com 3016 t1 and it failed.
I've tested from a workstation given a public ip address (bypassing the pix501) to a 3com 3016 and it failed.
I connected directly to the 3com 3016 and was able to successfully connect to the exchange server.
The above scenario was done from a different ip block than what my client has.
None of the ip addresses show to be on any blacklists.
I thought it might be the pix and the IDENT service, but logging shows there aren't any denied packets on port 113 and I also bypassed the pix and received the same failed result.
Also, on my client's network, this problem first appeared today (a monday) and was working fine the previous friday. No changes have been made on his network.
On a 3rd network where this connection also fails, they have a cisco pix 501 and an adit600 t1 router.
Other networks I tested this on have an ip in the same ip block as the client with the problem and telnet works just fine for them.
I'm not sure what I'm missing here (would senderid or SPF come into account here? I don't see why since I'm only accessing pop3). Any help or insight would be greatly appreciated.

Also to note, I've cleared xlate on the pix and have yet to go so far as restarting firewalls and routers.

Again, any input would be greatly appreciated and if I haven't been clear enough, I apologize and will try to paint a better picture based upon any followups.

Cheers!

Start your free trial to view this solution

Question Stats

Zone: Networking

Question Asked By: junebug74

Solution Provided By: junebug74

Participating Experts: 1

Solution Grade: A

Translate:

Loading Advertisement...

20080236-EE-VQP-29 / EE_QW_2_20070628