1. Kiyoshi Kodama, SE Japan 11-July-2008
Internal test
Fortinet Japan
Internal test : Confidential Outlook Express 6.0 (OE) doesn’t display properly for double bye character in mail subject field when FGT added Spam tag. Why?
Kiyoshi Kodama, SE Japan
11-July-2008

2. Fortinet Confidential AS tag simple test
Contents
Test purpose
I received question that reason why Outlook express 6.0 client (OE) doesn’t display properly for double byte character in subject field when FGT added spam tag.
I would like to take investigate it and try to find out which side either FGT or OE has problem on it.
Configuration
FortiGate 50A v3.00,build0662 (MR6 Patch2)
TP mode (Management IP: /24)
PC-1 connect to Internal port. Mail Server connect to external port.
Install several MUAs to PC1
MUAs : Outlook Express 6.0, Thunderbird , Becky , Hidemaru
Test scenarios
Enabled AS feature on FGT, Send/Receive by client self.
Server and PC-1 connected direct, create an to set character code in subject field at server.
Fortinet Confidential AS tag simple test

3. Fortinet Confidential AS tag simple test
Network Configuration
PC 1 is connecting to Internal port of FGT, Mail Server is connect to external port of FGT.
PC1 can send/receive through FGT.
Enable AS feature, triggered by in-correct URL. Like
PC-1 :
Mail Server :
Fortinet Confidential AS tag simple test

4. Fortinet Confidential AS tag simple test
Test scenario 1 (Outlook Express)
Create an to put double byte character in subject field, URL in message body field.
Send out the .
Fortinet Confidential AS tag simple test

5. Fortinet Confidential AS tag simple test
Test scenario 1 (Cont)
FGT check the domain name which is aaa.ccc is resisted in DNS Data base first, and then added spam tag in subject field if it isn’t exist in there.
After added spam tag in subject field that problem is occur with double byte character. It doesn’t display properly in subject field of OE (Outlook Express)
Let’s take investigate what happed on this.
Fortinet Confidential AS tag simple test

6. Fortinet Confidential AS tag simple test
Test scenario 2 (Thunderbird)
Ok, Let’s use another MUA which is Thunderbird has same issue on this?
Send and Receive through FGT, FGT added spam tag in subject field.
However, double byte character is properly display at subject field against OE.
What’s happen?
Fortinet Confidential AS tag simple test

7. Fortinet Confidential AS tag simple test
Trouble shooting. (Capture to SMTP/POP traffic)
Take to Packet capture about SMTP/POP traffic at PC-1 side.
We find out that two codes which uft-8 and iso-2022jp are exist in subject field when FGT added spam tag.
Note: FGT added utf-8 code, iso-2022jp is original code.
Subject: =?utf-8?Q?***Spam***?==?iso-2022jp?B?GyRCPVAycSQkJE4+bBsoQg==?=
PC-1 :
Mail Server :
Fortinet Confidential AS tag simple test

8. Fortinet Confidential AS tag simple test
Trouble shooting.(Cont)
FGT made something issue?
OK. Let’s Remove FGT from this network , both PC-1 and Server are direct connect.
It will clear for trouble shooting.
Logon Mail server.
Create an as following procedure.
# mail
# subject: =?utf-8?Q?***Spam***?==?iso-2022jp?B?GyRCPVAycSQkJE4+bBsoQg==?=
#. (dot and press enter key)
# CC (just press enter key)
PC-1 :
Mail Server :
Fortinet Confidential AS tag simple test

9. Fortinet Confidential AS tag simple test
Test result
Both MUAs are receive from mail server direct.
I can see same issue that exclude FGT. I confirm that OE has display issue, but Thunderbird haven’t it.
I have tried to take evaluation test with another MUAs which are Becky and Hidemaru also.
I could gather test result which is in the matrix.
OE has display issue.
MUA Name
Version
Display Properly?
Outlook Express
6.0
X (NG)
Thunderbird
O (OK)
Becky O
Hidemaru
5.0.7
Fortinet Confidential AS tag simple test

10. Fortinet Confidential AS tag simple test
Summary
FGT added spam tag to subject field with utf-8 character code.
Two codes are exist in there which are utf-8 and ISO-2022-JP after that.
OE doesn’t display properly, but another MUAs is looks OK.
It seems that OE has something limitation that will their specification.
FGT haven’t issue with another MUAs.
If customer has issue with OE and FGT AS tag. You will tell them about that.
Fortinet Confidential AS tag simple test

11. Fortinet Confidential AS tag simple test
Thank you
Fortinet Confidential AS tag simple test