[Openswan Users] Help! - Unable to send email (exchange/mapi) with attachments from remote (VPN connected) site using WinXP

[Darius]

Thanks Ken, MTU size was indeed the problem. It needed to be reduced on 
XP at least, reducing it on the Exchange server intially wasn't enough 
to make the problem go away (I'll increase it on the Exchange server 
later to see if the problem originates on the XP side). I've not yet 
compared XP and Win2K packets but perhaps XP is setting the "don't 
fragment" bit or not doing MTU path discovery properly (since it was 
receiving ICMP type 3 code 4 packets) or maybe its due to some other 
interaction involving elements as-yet-unknown by me.

Thanks again,
Darius

Ken Bantoft wrote:

>On Mon, 26 Apr 2004, Darius wrote:
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>>Greetings,
>>
>>We want to switch our remote office Win2K desktops to WinXP (Ok, ok - if 
>>you are already jeering then please know that closed, proprietry OS's 
>>are not my first choice either). Our remote offices use FreeSWAN (1.97 
>>on RH 7.3) to get to an Exchange 5.5 server at our head office (where 
>>Debian, RH  and snapgear(linux/FreeSWAN) are used on servers, routers). 
>>All Win2K/XP desktops are using Outlook 2000 (MAPI) to communicate with 
>>Exchange.
>>
>>Posting this problem here and expecting a soltion might be a longshot; 
>>chances are this isn't a FreeSWAN config problem, but my testing 
>>environment can't eliminate our FreeSWAN VPN setup from being part of 
>>the problem at the moment. I'm hoping someone with a similar environment 
>>will see this and have some constructive suggestions about how to fix 
>>this problem, or diagnose the problem without replacing FreeSWAN with 
>>another VPN product, or tell me that 
>>WinXP/Outlook2K/Exchange5.5/FreeSWAN works for them !
>>
>>    
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>Set the MTU on the Exchange server to 1400.  I've dealt with similar 
>issues with Exchange - it seems the PMTU discovery breaks every other 
>service pack or so.
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