sophos email appliance how to remove subject information from reply email using regular expression

Below is what this person stated from support on this matter but I have seen this done....I just can't remember how?? if anyone remembers please reply!!

Hello Philip,

This email is regarding your service request number 8572775.

Unfortunately that us not possible, appliance will add that keyword every time when policy triggered.

Please let us know in case you need any further assistance.

Regards,

Rajesh Dolani
Sophos Technical Support
https://www.sophos.com/en-us/support/technical-support.aspx

Support Knowledge Base: https://community.sophos.com/kb
Follow us on Twitter @SophosSupport
Sophos Community (discussion forums): https://community.sophos.com

SOPHOS - Security made simple

-----Original Message-----
From: guthriep@ffbf.com
Sent: 2019-Jan-14 07:46 PM
To: esasupport@sophos.com,
Cc:

If this cannot be done,  is there a way to ONLY have the External show up in email once?  Ex.  When external email  passes thru the mail appliance from external
user it gets flagged EXTERNAL  then is there a way to ONLY have the email tagged only the one time??

From: Sophos Support <esasupport@sophos.com>


Sent: Monday, January 14, 2019 8:55 AM

To: Phillip Guthrie <guthriep@ffbf.com>

Subject: [EXTERNAL] RE: [#8572775] sophos email appliance how to remove subject information from reply email using regular expression

Hello Philip,



This email is regarding your service request number 8572775.



There is no such option to create any policy to remove keyword from subject.



We can create policy to add keyword.



Please let us know in case you need any further assistance.



Regards,



Rajesh Dolani

Sophos Technical Support

https://www.sophos.com/en-us/support/technical-support.aspx




Support Knowledge Base: https://community.sophos.com/kb

Follow us on Twitter @SophosSupport

Sophos Community (discussion forums): https://community.sophos.com



SOPHOS - Security made simple

-----Original Message-----

From: guthriep@ffbf.com

Sent: 2019-Jan-14 06:44 PM

To: esasupport@sophos.com,

Cc:

EDN INFORMATION

-------------------

Name: Phillip Guthrie

Company: FFBF

Description: The below policy does tag incoming email from external email correctly however, when a user replies to external mail the external is still in the subject. I want the [external ]removed when a person reply's to external mail. I would like to accomplish
this using regular expression if possible.

Hi Phillip,

depending on what your trying to do you may find it better to add/delete X-headers rather than modifying the subject lines.   I also noticed the reg-ex may not perform exactly how you like.  something like .

^((?!RE:).)*$ 

that would look for the exact match.. then you could make a rule that is like... if-not exists  regular expression, then remove subject.

adding or searching for the X-header would allow you to more transparently scan the mail .. without trying to scan each message subject..  so rather than use Subject .. have another rule that looks for or removes X-headername  ..