Chapter 32 Email Security
ZyWALL ATP Series User’s Guide
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32.4.2 Regular Expressions in Black or White List Entries
The following applies for a black or white list entry based on an email subject, email address, or email
header value.
• Use a question mark (?) to let a single character vary. For example, use “a?c” (without the quotation
marks) to specify abc, acc and so on.
• You can also use a wildcard (*). For example, if you configure *def.com, any email address that ends
in def.com matches. So “mail.def.com” matches.
• The wildcard can be anywhere in the text string and you can use more than one wildcard. You
cannot use two wildcards side by side, there must be other characters between them.
• The Zyxel Device checks the first header with the name you specified in the entry. So if the email has
more than one “Received” header, the Zyxel Device checks the first one.
32.5 Email Security Technical Reference
Here is more detailed email security information.
Mail Subject
Keyword
This field displays when you select the
Subject
type. Enter up to 63 ASCII characters of text to
check for in email headers. Spaces are not allowed, although you could substitute a
question mark (?). See
for more details.
Sender or Mail Relay
IP Address
This field displays when you select the
IP
Address
type. Enter an IP address in dotted decimal
notation.
Sender or Mail Relay
IPv6 Address
This field displays when you select the
IPv6 Address
type. Enter an IPv6 address with prefix.
Netmask
This field displays when you select the
IP
type. Enter the subnet mask here, if applicable.
Sender E-Mail
Address
This field displays when you select the
type. Enter a keyword (up to 63 ASCII
for more details.
Mail Header Field
Name
This field displays when you select the
Mail Header
type.
Type the name part of an email header (the part that comes before the colon). Use up to 63
ASCII characters.
For example, if you want the entry to check the “Received:” header for a specific mail
server’s domain, enter “Received” here.
Field Value
Keyword
This field displays when you select the
Mail Header
type.
Type the value part of an email header (the part that comes after the colon). Use up to 63
ASCII characters.
For example, if you want the entry to check the “Received:” header for a specific mail
server’s domain, enter the mail server’s domain here.
See
for more details.
OK
Click
OK
to save your changes.
Cancel
Click
Cancel
to exit this screen without saving your changes.
Table 226 Configuration > Security Service > Email Security > Black/White List > Black/White List > Add
LABEL
DESCRIPTION
