UIDLs HOWTO?

[olaf.krause]

I have a question related to the UIDL entries in the registry. For what exactly are they used (OK know that an UIDL is an email ID) and under which circumstances wingate writes them to the registry - when are they removed?

I'm asking because on a regularly basis mail were NOT downloaded by wingate and the list of UIDLs is getting longer and longer. After removing the UIDL entries manually the mails were donwloaded.

by mistake I also posted in the BETA section
http://forums.qbik.com/viewtopic.php?p=17807

[olaf.krause]

I have a question related to the UIDL entries in the registry. For what exactly are they used (OK know that an UIDL is an email ID) and under which circumstances wingate writes them to the registry - when are they removed?

I'm asking because on a regularly basis mail were NOT downloaded by wingate and the list of UIDLs is getting longer and longer. After removing the UIDL entries manually the mails were donwloaded.

Nobody able to give me some hints?

[jamesc]

I have asked some of my colleagues about this. One of us will advise.

[adrien]

Hi Olaf.

As you know, the UIDL of a message is intended to uniquely identify that message on that server. WinGate uses this to see if it has already downloaded that message before. This is so that if WinGate is not deleting messages from the server, it doesn't repeatedly download the same messages over and over.

When it starts a POP3 collection cycle on an account, WinGate goes through all the UIDL values for that account, and changes the REG_DWORD value associated with the UIDL to 0.

WinGate then checks the server, and for each message in turn, requests the UIDL (using the UIDL message-no syntax). The server replies with the UIDL for the specified message, if WinGate finds that UIDL value in the registry, it knows it has seen it before, and it sets the value for that UIDL to 1, if not, it downloads the message, and if that succeeds, adds the UIDL with a value of 1 to the registry.

After all the messages have been checked, WinGate deletes any UIDL values that are still 0, since this means that message is no longer on the server (presumably has been deleted by another POP3 agent).

If you delete the UIDL values out of the registry, WinGate will think it has not seen the message before, and will download it again, storing the UIDL value back in the registry.

If the messages are not being deleted from the server, is this supposed to be WinGate's job? E.g. do you have WinGate configured to delete the messages, or under what circumstances?

Also some POP3 servers don't really support UIDL properly. Do you know if your POP3 server supports UIDL?

Adrien

[olaf.krause]

Hi Olaf.
...
When it starts a POP3 collection cycle on an account, WinGate goes through all the UIDL values for that account, and changes the REG_DWORD value associated with the UIDL to 0.

OK

WinGate then checks the server, and for each message in turn, requests the UIDL (using the UIDL message-no syntax). The server replies with the UIDL for the specified message, if WinGate finds that UIDL value in the registry, it knows it has seen it before, and it sets the value for that UIDL to 1, if not, it downloads the message, and if that succeeds, adds the UIDL with a value of 1 to the registry.

After all the messages have been checked, WinGate deletes any UIDL values that are still 0, since this means that message is no longer on the server (presumably has been deleted by another POP3 agent).

So after a mail collection there should be NO UIDLs with value 0? In my case I have 50% UIDLs with value 0 and at the moment no mails left at my ISP mailbox.

If the messages are not being deleted from the server, is this supposed to be WinGate's job? E.g. do you have WinGate configured to delete the messages, or under what circumstances?

I configured wingate in that way that it should delete mails after a successfull delivery

Also some POP3 servers don't really support UIDL properly. Do you know if your POP3 server supports UIDL?
Adrien

If not does wingate generate random UIDLs?

I now have removed all entries and switched on debugs (mailbox is empty). If it happens again I will send you the logs...

thx

Olaf