Figure 6.8.

Authorized Client Backups Active:
With this option selected, a backup can only be made from (a) certain IP-address(es). Fill in one or more IP-address in the fields that appear, and save the settings by clicking Save.

Password Authentification Active:
When checked, a password authentication mechanism can be activated to make sure that only certain individuals can make and restore backups.

Making and restoring a backup:
Make a new directory where the backup must be saved. This can be both locally and on a network drive. Be aware of the fact that a backup can amount up to several gigabytes in diskspace, especially when IMAP mail is being used.

	Caution:
	easygate.exe does not take free diskspace into account. Before starting a backup-task, make sure that there is enough free space on the harddisk where the backup files are to be saved on.

Figure 6.11.

Email server enabled:
This is where you can activate exchange4linux’ Email server functionality. It is the main switch, which has to be activated at all times. If you remove the check, mail will NOT be sent or received. This should only be used to temporarily disable the mailserver on exchange4linux.

Mail domain:
This is the name of the mail domain. This is usually the domain-name, for instance YourCompany.com, sometimes with a subdomain in front of it (e.g. marketing.YourCompany.com). Your provider usually supplies you with this information.

Mail relay host:
Here the mailhost of your provider must be filled in (usually something like smtp.provider.nl). Your provider usually supplies you with this information. When exchange4linux has to function as mail relay host itself (which we usually recommend), this field needs to remain empty. This is only advised for permanent internet connections.

	Caution:
	It is strongly recommended to always use the hostname of the mail relay server instead of its IP-address, since providers sometimes change the underlying IP-addresses of hostnames without warning you in advance. This causes exchange4linux to attempt to connect to a non-existing IP-address.

Relay server SMTP authentication enabled:
When the provider uses SMTP authentication, this option needs to be checked.

Relay server SMTP authentication user id:
Here you fill in the username that has been supplied to you as SMTP authentication. Consult your internet provider when this value is unknown.

Relay server SMTP authentication password:
Fill in the corresponding password here.

Maximum Email message size (in bytes):
Use this field to limit the size of all incoming and outgoing mail, both internal and external. Please pay attention to the fact that an attachment causes its message to become about 1.4 times the size of this attachment. For example, email with a 5 MB attachment will be 7 MB in size.

Figure 6.13.

Email fetching enabled:
Here you can (de)activate the Email fetching scheme. If you deactivate Email fetching, mail will not be sent and retrieved anymore. However, mail will be sent and retrieved when there is an internet connection. Usually this function should be activated.

Extra domains (separated by spaces):
This is where extra domains can be inserted, for which exchange4linux should accept incoming Email. For example, besides YourCompany.com there is also YourBrandname.com. Multiple entries have to be separated by a space.

Deliver Email to local alternative mailserver:
When mail is NOT retrieved by SMTP, but by multidrop POP3, it can be forwarded to another mailserver. When this box is checked (and after clicking Save), a new field is created where you can enter the IP-address of the alternative mail server. This function does not work with (batched) SMTP! Since batched SMTP is the most often used method of Email delivery, this function is obsolete in most cases.

Forward Undeliverable Email to:
This setting only works when the Email is fetched by means of multidrop POP3. If you use batched SMTP, this setting will not have any effect. Undeliverable Email will be, in case of SMTP, returned to the sender with the error message User unknown.
 
When mail is being fetched with (multidrop) POP3:
An existing mailbox-name has to be entered here. All mail that exchange4linux cannot deliver because the local recipient is not a valid user will be routed to this mailbox. This happens when someone makes a typing-error in the e-mail address. For instance: an email is sent to boob@yourcompany.com. Within exchange4linux this address is unknown. However, there is a user called bob@yourcompany.com. This way the message will arrive and the user who checks this mailbox can forward the mail to the intended recipient.
In general this setting makes sure that all mail for your domain, that is all mail sent to a user @yourcompany.com will arrive. Normally admin is the desired recipient for undeliverable messages.

Figure 6.14.

Add new Email fetch server:
In this section you can select from which POP3 servers the mail has to be retrieved. This is only necessary when you do not use batched SMTP.
Also other servers can be entered here. For instance, the mailserver of an already present mail subscription. The setting can be altered (click on the arrow pointing to the right) or a new server can be added (click on the arrow pointing downwards).

Position/order:
This is the rank the server in question has. If there are multiple servers, you can decide on the sequence of connections to the different mailservers (more important servers could be checked first).

Comment:
A description can be entered here. This will appear under the server-name in the server-list. For instance POP3 at providername.

Email POP3 host:
This is the mailhost-name of the provider. Normally your provider has given this information to you. In general the value resembles pop3.provider.com

Email POP3 username:
This is the username of the e-mail account. Often (though not always) it is the same as the access-account username.

Email POP3 password:
The password that corresponds to the POP3 account mentioned above.

Forward to:
Here you can indicate which email address the emails need to be forwarded to. This field generally is set to wildcard (“*”). It makes sure that messages are delivered at the recipient that the sender addressed the message to. If a mailbox-name is filled in here, all mail will be sent to this mailbox, regardless of the intended recipient. This is useful if mails need to be fetched from an old e-mail account or e-mail domain, and all of these messages need to be sent to another mailbox (like OldMailDomain@YourCompany.com)

	Caution:
	The wildcard-setting can only be used in combination with a multidrop POP3-account. Your provider can inform you on this matter.

Figure 6.16.

Email transfer start time:
Start time for the mail-transport. For instance, it could be set to half an hour before the normal starting time of the users. This way, Email has already been fetched by the time users want to read it.

Email transfer end time:
End time for the mail-transport. Please be aware of the fact that after this time no more mail is being sent and received. When employees often work late, a sensible time like 20:00 can be filled in here.

Minimum Email Transfer Pause:
This is the minimum time that must pass before a new connection is initiated again. With this setting, the number of connections made can be limited. There would be unnecessary costs incurred if every 5 minutes a new connection is made because there is another message in the send queue. A sensible value is between 15 and 30 minutes for an ISDN connection. This parameter works in conjunction with the settings in the following paragraph. Note that for a flat-fee connection the values entered here can be much more strict.

Maximum Email Transfer Pause:
This is the maximum time that will elapse before a new connection is initiated again. A sensible value is between 30 and 60 minutes for an ISDN connection.

Figure 6.17.

Deliver Email immediately:
A new e-mail message delivered to exchange4linux will be sent immediately. When you have a flat-fee internet connection, like ADSL, this is the recommended method since there is a minimal delay between sending and receiving mail.

Save messages and deliver them after fetching Email:
With this method checked, exchange4linux will send Email according to the settings made in the menu "auto fetch days" (Section 6.5.6) and "auto transfer schedule" (Section 6.5.7). This method saves connection costs when ISDN is being used, since there will not be made an internet connection for every e-mail message.

Figure 6.19.

Delay after connection error:
If errors should occur while making a connection, then this time must elapse before trying to connect again. This prevents immediate attempts to reconnect after a failed connection.

Email check send queue after send error delay:
The period of time that elapses after there has been a connection-error with a transfer action. A logical value is somewhere between the settings minimum and maximum Email transfer-pause. The send queue is checked for not yet delivered mail. A connection is only made when mail to be sent is queued.

Figure 6.20.

Spamfilter enabled:
The spamfilter can be (de)activated here.

How many points before a message is considered spam:
The score system decides when a messages is considered to be spam, based on several characteristics of spammail. The lower the value set here, the higher the risk of getting false positives: messages marked as spam while they are actually not. A value of 5 usually results in very few false positives, while most of the spammail is being filtered out.

Rewrite e-mail subjects to flag them as spam:
When a message is marked as spam, its subject can be changed by putting a common text in front of it. Fill in this subject in the field that appears when this option is checked. Due to this common subject line, a user can easily discover spammail in its mailbox.

Encapsulate spam in an attachment in the report e-mail:
The original spammessage can be included as an attachment with the report that will be sent to the recipient. The report includes information on the distributor of the message and the reason for marking the message as spam.

Use terse version of the spam report:
Select this option to send just a minor report to the recipient of the spammessage.

Bayes detection system with auto-learning mode enabled:
The Bayes selection system is a complex method that nuances the before mentioned score when deciding on the status of each individual message. This is being done by looking at messages that a user received in the past and by using a special weighing system to decide on the possibility of a message being spam. It is advised to activate this setting, since it further decreases the risk of false positives while spam is recognized better.

Spam filter Real-time Black List (RBL) network check enabled:
With this option enabled the spamfilter checks the sender of a message by using several on-line blacklists. These databases contain extensive information on networks and mailservers that distribute spam. As soon as a message originates from such a server points are added to the score of the message, so that it might be considered spammail.

Restart spamfilter:
When changes have been made to the configuration of the spamfilter, it can be restarted without having to reboot the exchange4linux server. Just check this option and click Save. Note that due to a changed profile, there will still be a notification that the system must be rebooted in order to activate the new profile.

Figure 6.21.

Spamfilter enabled:
Always leave this option checked, unless you want to disable the spamfilter completely.

Spamfilter whitelist enabled:
This option (de)activates the whitelist as described above.

Spamfilter whitelist:
Add e-mail addresses and domains here to make sure that their messages will not be marked as spam.

	Caution:
	insert every entry on a new line. A domain must be defined *@domein.com, an e-mail address must be inserted completely.

Restart spamfilter:
Use this option to restart the spamfilter directly after changes have been made to its configuration.

Figure 6.22.

Spamfilter enabled:
Always leave this option checked, unless you want to disable the spamfilter completely.

Spamfilter blacklist enabled:
This option (de)activates the blacklist as described above.

Spamfilter blacklist:
Add e-mail addresses and domains here to make sure that their messages will always be marked as spam.

	Caution:
	insert every entry in a new line. A domain must be defined *@domein.com, an e-mail address must be inserted completely.

Figure 6.25.

Fax enabled:
Check this box to enable the faxserver.

MSN:
Fill in the MSN number (without 0) which will be used to send and receive fax messages. As soon as a fax call is made to this MSN number, exchange4linux will accept the incoming connection.

Full fax number:
This number will be attached to every outgoing fax message.

Fax sender ID:
The value filled in here will also accompany an outgoing fax message and will appear on the LCD screen of the recipient’s fax machine.

Area code (without 0):
Insert the area code (without 0).

Country code:
Insert the country code here, eg. for The Netherlands 31 and for Germany 49.

Interlocal prefix:
The prefix that is placed in front of an interlocal number, usually a 0.

International prefix:
The prefix that is placed in front of an international number, usually 00.

	Caution:
	Make sure that the address range you allow the DHCP-server to choose from (see Chapter 7) falls within the network that is defined here. A wrong entry can lead to a non-operating network, so it is important to pay attention what you enter here.

Figure 6.26.

Internal Ethernet port enabled:
This is where you (de)activate the connection to the internal network. Normally this item should be activated.

Network address:
This is where the base-address of your network should be inserted. Do not fill in a subnet address. When the internal network is a subnet, then fill in the C-class or B-class network address that lies above it and add the subnet address to the menu item Name Server - Name server settings - Alternative Name server network address.

	Important:
	Fill in a network address from one of the private ranges. Don’t use the 10.0.0.0 A-class network. Obviously it is not allowed to use another A-class network, since the remaining A-class networks are reserved official IP-ranges.

Internal IP-address:
The IP-address that is to be used by exchange4linux.

Broadcast address:
The broadcast address of the network. This address should always end on .255 with a C-class network and on .255.255 in case of a B-class network. When an alternative IP-range is being used (eg. in case of subnetting), there should still be a C-class or B-class broadcast address. The correct broadcast address can now be added to the menu item Name Server - Name server settings - Alternative Name server network address.

Netmask:
The netmask of the network. It usually ends on .0 with a C-class network and on .0.0 with a B-class network. However, this is not always true: In case of subnetting there should still be a C-class or B-class netmask. The correct netmask can now be added to the menu item Name Server - Name server settings - Alternative Name server network address.

Gateway/default route:
Fill in the gateway here. This can be an internal router, but also a DSL- or cable-modem/router.

	Caution:
	When using ADSL by KPN (before Mxstream) in The Netherlands, this field MUST remain empty.

Figure 6.27.

DHCP server activated:
Here the dynamic assignment of IP-addresses can be (de)activated. This function needs to be deactivated only if all computers in the network have a fixed IP-address.
When there is already a DHCP server active in your network, some settings of the exchange4linux server have to be added to its configuration. For DHCP this implies the values for default route/gateway, internal domain and Name server (if applicable also the WINS server). In this case the exchange4linux DHCP server can safely be disabled.

	Caution:
	The following settings have to comply with the configuration of the internal network and with your general network configuration. Incorrect entries can lead to a non-functioning network.

DHCP IP Pool Start Address:
First IP-address of the pool from which addresses will be assigned dynamically.

DHCP IP Pool End Address:
Last IP-address of the pool from which addresses will be assigned dynamically.

Default Lease Time (HH:MM):
This is the default lease time for a dynamically assigned IP-address. You can leave this setting unaltered. Change it only in special situations.

Max Lease Time (HH:MM):
This is the maximum lease time of a dynamically assigned IP-address. You can leave this setting unaltered. Change it only in special situations.

Figure 6.28.

EasyShare Service Enabled:
This setting (de)activates the exchange4linux fileserver functionality. When it is deactivated, the fileserver is shut down and it will no longer be possible to reach its fileshares.

Figure 6.29.

	Caution:
	To make use of the Windows network services, users of EasyShare need to log onto the network with their exchange4linux mailbox-name and password. When this is not the case, a connection to the fileshares is not possible from a Windows workstation. Therefore it is advised to use the same log-in for both the network and the exchange4linux server.

Windows network service Enabled:
When activated, access to EasyShare files and folders is possible from Windows PCs (when the user has got access rights). For example, one can connect to the fileshares by means of attaching a network drive letter to them within the Windows Explorer.

Windows WINS Enabled:
With this function activated, the Windows Internet Name Service (WINS) will be used. This is necessary when no other WINS server is active within the network and users wish to connect to the exchange4linux network shares. By default WINS is activated. When there is already a WINS server present within the network, it is advised to disable this function on exchange4linux. Do keep in mind to make a manual entry in the existing WINS server with the IP-address of exchange4linux.

Windows Workgroup/domain:
Here the workgroup name that has been defined in the Network Neighborhood of Windows NT/95/98/2000/XP can be filled in. The exchange4linux server will then be visible within this workgroup. Alternatively the name of the NT-domain can be filled in.

Figure 6.30.

Internal host name:
Define the internal hostname of exchange4linux here. By default it is set to exchange4linux. Normally you do not have to change this value.

Internal domain:
The internal domain suffix must be filled in here. When there is not yet an internal domain suffix in use, it is advised not to change this value.
In case of Apple users the suffix must include a . (dot), eg. local.intranet. This is the domain suffix that, in case of fixed IP-addresses, must be inserted in the DNS searchlist of the workstations. By default it is set to local.intranet.

Alternative Name server network address:
In special cases you can enter an alternative network address here. This could be necessary in case of a WAN configuration. The result is that exchange4linux will build a Name server for the network defined here instead of for the network defined at Internal network. This way, one can make sure that a B-class network Name server is being built, while a C-class network has been configured.

Name server forwarder 1,2,3:
When this function is activated, up to three IP-addresses of other name servers can be included, which will be queried respectively. Usually the name servers of the ISP are filled in here. At least 2 IP-addresses have to be filled in, which have been supplied to you by your provider.