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Outlook2000 POP3 duplicates messages

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by phingers 1 view

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I have a client running Outlook connecting to an Exchange server using a LAN. I have also set up Internet email using POP3 so they can connect offsite using dial-up.
They synchronize their folders upon exiting, but when using offline folders and the dial-up they get mail in their inbox that they have already read earlier that day. Is there an option I have not set or is this just the way POP3 works? If so what is the alternative. They unfortunatley do not want to use Outlook Web Access andbeing my MD I cannot force them to!

7 replies

by lordinfidel

You are using Exchange natively and POP3.

You need to choose one or the other. You should not use both to access the same account.

If your client wants to keep all mail stored on his local drive fine, if it crashes he loses all of his mail. My advice would be get rid of exchnage and go with sendmail. Your not using exchange at that point for what is was designed to be anyways.

If he wants to have the security of exchnage then he needs to abide by it's rules.

You can connect usingthe native exchange client to the exch server, but it would (is recccomended, highly) that a secure connection thru the firewall be obtained.

But since you are allowing POP email thru and that is passing his username and passoword in clear plain text thru the net. I am assuming that security is not an issue here.

Just allow tcp 138 and 139 thru the firewall to the exchnage server. Since people can already sniff and grab his network passwords anyways, why not give him what he wants.

I'm not trying to be cruel, but this is the atitiude/stance you have to take with him. Afterall, the client/enduser knows nothing about security or the ramifications of their actions. It's our responsibility to draw the line in the sand and tell them what will happen when that line is crossed.

BTW- If you do get him to do web access, which in my opinion is great for the firewall vpn non networks. Generate your own cert and use SSL. At least make some attmept to coneal the user name and password. Fine they will get an annoying pop-window. But at least it's better then me, the hacker, getting the coveted U/P to hack into your network with.

by phingers

Thanks for the info.

I think the solution, as you say, is to explain to him the security risks involved in using POP3 and that POP3 and exchange are not designed to work this way. The problem is that we used Lotus Notes before which enabled him to download only those emails that he had not read and then use offline.
The benefits of using Exchange and outlook far outwiegh this (slight) loss of function, and the web access has been set up secure so it will prompt for a username, passwordand domain when accessing. If he uses the exchange native clinet he will be using two email clients (native offline and Outlook on the LAN) whereas he needs to use only one.

I shall ensure the line in the sand is clear!

by lordinfidel

For my users who travel (ie with laptops), I have set up a vpn connection between them and my firewall thru the public net.

That is they dial-up to the net, and the client side vpn software contacts our firewall and estabilshes a vpn.

Once they have the vpn espatbilshed, they can act as if they are on the local lan.

In their outlook clients, they are set up to be in coprortate/workgroup using exchange only. No other accounts are set up in the services area.

For my users who are at home who want to check their e-mail, they use OWA. Now, you said that it prompts them for their domain name.... That's find, but is it ssl? Without SSL, propmting for the U/P/domain name does nothing.

Instead allow for basic auth, get a securecert. (On the IIS server, set up a local CA, then on the exchange site, request a new key -1024 bit-, install the cert on the site and require https to connect)

When the user goes to the https site, they will get a cert problem, just click yes and the connection is now protected via ssl.

Another way to do it, is to set up IMAP. At least the mail stays on the server. But you still have the security issues.

by basil.cinnamon

I have a similar duplication problem but we do not use Exchange. We use Outlook to access an ISP's email server with POP3. Every so often users get repeats of messages they have read; this is not an Outlook settings issue because all our users have the same settings and no settings ever change. (One of the settings is "Leave msgs on server for 7 days" in case user loses message, or picks it up on the road then wants to pick it up at the office,too. This setting is not the cause of duplicates.) I believe the problem has to do with how Outlook keeps track of the messages it has already read; this may get corrupted so it thinks that no messages have been read and repeats them all.

Does anyone know where Outlook keeps this info?

by basil.cinnamon

After endless searching, I found the %$#@!&* place where Outlook keeps the list of emails it's read. In W98, it is in a file called MSINnnnn.RHS located in "c:\Windows\Application Data\Microsoft\Outlook\MSINnnnn.RHC" where nnnn are four random digits that appeard to be a hash, one such file per Internet Email service in the user's profile. If this file gets deleted or damaged, Outlook will go back to the email server for that account and download all the new and old messages as unread.

If you copy this file to the equivalent folderin another PC and run Outlook on the same name user profile with the same internet email account, it will prevent the re-downloads from happening.

It took me years to dig this one up. I give myself 1,000,000 points.

by lordinfidel

Most POP servers, once you download the e-mail, the e-mail is no longer on the server.

The above only works if you have "Leave a copy of e-mail on Server" Checked. (You should only use this option when using corporate or workgroup)

Exchange uses it's own mechanism for viewing e-mail. Since you are not really viewing the e-mail on your system, but rather on the server.

The problem runs into using POP and exchnage to access the same account. You will run into duplicate e-mails. That is unavailable.

Best practices say to use one or the other to access a mailbox. Not both.

by basil.cinnamon

You're correct in that, to leave msgs on a POP3 server after the first download, you need to check Leave msgs on Server for N days. That's our default, because roadwarriors may pick up msgs on the road, yet want their desktop to pick them up when they get back, rather than synching laptops. It also backs up msgs picked up at a desktop but subsequently lost.

In any case, this is NOT what causes the dupes; this setting has been our standard for a couple of dozen users for several years. The dupes come about if the file I mentioned earlier gets damaged or lost.

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