Changes

A local area network (LAN) is the system of wires and other hardware that connects the computers within your office and allows them to communicate with one another. An ethernet LAN is the most common type. Ethernet refers both to a kind of connection and to a protocol for how Internet data packets travel around your network.

A local area network (LAN) is the system of wires and other hardware that connects the computers within your office and allows them to communicate with one another. An ethernet LAN is the most common type. Ethernet refers both to a kind of connection and to a protocol for how Internet data packets travel around your network.

The hub, a common component of an ethernet, serves as a point of interface between computers on the network. Each computer on your network is connected to the hub using an ethernet network cable. Different hubs operate at different speeds: slower hubs, operating at 10 MB/sec, are suitable for small networks; faster hubs, operating at 100 MB/sec, are suitable for larger networks. Switching 10/100 MB hubs can operate at either speed, and provide a good way to upgrade your network gradually.

The hub, a common component of an ethernet, serves as a point of interface between computers on the network. Each computer on your network is connected to the hub using an ethernet network cable. Different hubs operate at different speeds: slower hubs, operating at 100 Mb/sec, are suitable for small networks; faster hubs, operating at 1 Gb/sec, are suitable for larger networks. Switching 100Mb/1 Gb hubs can operate at either speed, and provide a good way to upgrade your network gradually.

An ethernet adapter, also called an ethernet card or network interface card (NIC), connects each computer to the ethernet LAN. An server with a dedicated Internet connection requires two ethernet adapters; one connects it to your LAN and the other connects it to the external network that leads to your ISP. If your server connects to your ISP using a modem or ISDN adapter, it only requires one ethernet adapter.

An ethernet adapter, also called an ethernet card or network interface card (NIC), connects each computer to the ethernet LAN. An server with a dedicated Internet connection requires two ethernet adapters; one connects it to your LAN and the other connects it to the external network that leads to your ISP. If your server connects to your ISP using a modem or ISDN adapter, it only requires one ethernet adapter.

* SME has IP Address a.b.c.d

* SME has IP Address a.b.c.d

* SME has domain name mysmeserver.com

* SME has domain name mysmeserver.com

* Remote_User is configured to use Other_DNS for DNS lookups

* '''Remote_User''' is configured to use '''Other_DNS''' for DNS lookups

If Remote_User tries to browse to http://mysmeserver.com, his computer asks Other_DNS how to find 'mysmeserver.com'.  Other_DNS server then

If Remote_User tries to browse to http://mysmeserver.com, his computer asks '''Other_DNS''' how to find 'mysmeserver.com'.  '''Other_DNS''' server then

* asks the Root_DNS servers for the Registrar in charge of 'mysmeserver.com'

* asks the '''Root_DNS''' servers for the '''Registrar''' in charge of 'mysmeserver.com'

* asks the Registrar for the DNS_Server that will answer queries about 'mysmeserver.com'

* asks the '''Registrar''' for the '''DNS_Server''' that will answer queries about 'mysmeserver.com'

* asks the DNS_Server for the IP address of 'mysmeserver.com'

* asks the '''DNS_Server''' for the IP address of 'mysmeserver.com'

* saves the answer in its local cache for the amount of time specified by the administrator of the DNS record at DNS_Server.

* saves the answer in its local cache for the amount of time specified by the administrator of the DNS record at '''DNS_Server'''.

If, on the other hand, Remote_User asks for information about your IP address (a.b.c.d), his DNS server

If, on the other hand, '''Remote_User''' asks for information about your IP address (a.b.c.d), his DNS server

* asks the Root_DNS servers where d.c.b.a.in-addr.arpa is registered.

* asks the '''Root_DNS''' servers where d.c.b.a.in-addr.arpa is registered.

* asks the Registrar where to get more info about d.c.b.a.in-addr.arpa.  This is probably but not necessarily Your_ISPs_DNS.

* asks the '''Registrar''' where to get more info about d.c.b.a.in-addr.arpa.  This is probably but not necessarily '''Your_ISPs_DNS'''.

* asks the host indicated by the Registrar (probably Your_ISPs_DNS) what name belongs to 'd.c.b.a.in-addr.arpa'.  The return value is almost always a generic filler based on your IP address unless you contact your ISP and ask them to change the PTR data for your IP address.

* asks the host indicated by the '''Registrar''' (probably '''Your_ISPs_DNS''') what name belongs to 'd.c.b.a.in-addr.arpa'.  The return value is almost always a generic filler based on your IP address unless you contact your ISP and ask them to change the PTR data for your IP address.

Basically, PTR records are managed by the organization that controls the IP address (which makes sense, if you think about it).

Basically, PTR records are managed by the organization that controls the IP address (which makes sense, if you think about it).

SPF (Sender Policy Framework) records are added to the DNS zone record for domain names. Many receiving mail servers now require sending mail servers to have properly configured SPF records for the domain(s) being sent from. Failure to have SPF records can result in mail being rejected by mail servers eg Hotmail servers will reject mail that comes from mail servers without SPF records.

SPF (Sender Policy Framework) records are added to the DNS zone record for domain names. Many receiving mail servers now require sending mail servers to have properly configured SPF records for the domain(s) being sent from. Failure to have SPF records can result in mail being rejected by mail servers eg Hotmail servers will reject mail that comes from mail servers without SPF records.

The SPF entries are added to your external DNS records. They are not configured on the sme server.

The SPF entries are added to your external DNS records which are hosted by your connectivity ISP. They are not configured on the sme server.

See http://www.openspf.org/  

See [http://www.open-spf.org/ here].

Here is a test site at Microsoft/Hotmail where you can check if SPF records are configured for your domain.

Here is a [https://mxtoolbox.com/spf.aspx test site] where you can check if SPF records are configured for your domain.

http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/default.aspx

Different providers have different mail acceptance policies.

Look for tech support pages for the provider.

Look for tech support pages for the provider.

References:

References:

http://forums.contribs.org/index.php/topic,42373.0.html

http://forums.contribs.org/index.php/topic,42373.0.html

=====Dynamic DNS Services=====

=====Dynamic DNS Services=====  

If your IP address is assigned dynamically, you may find it helpful to use a dynamic DNS service. A dynamic DNS service provides you with an automated way to notify them whenever your IP address changes so that they can immediately publish new DNS records for your domain. Without dynamic DNS, you would have to contact your ISP to have them change your DNS records, and your web site and other services would be unavailable for several days until the change was processed. You can easily enable the usage of a dynamic DNS service by selecting it on your server console.

If your IP address is assigned dynamically, you may find it helpful to use a dynamic DNS service. A dynamic DNS service provides you with an automated way to notify them whenever your IP address changes so that they can immediately publish new DNS records for your domain. Without dynamic DNS, you would have to contact your ISP to have them change your DNS records, and your web site and other services would be unavailable for several days until the change was processed. You can easily enable the usage of a dynamic DNS service by selecting it on your server console.

A dynamic DNS service can be a great solution when used with a dedicated connection. With a typical dialup connection, your IP address changes much more frequently (possibly every time your server connects) and, because the server only connects intermittently, there is a delay in informing the dynamic DNS service of the change. This means that the risk of misdirected information is much greater with a dialup connection. For this reason, we recommend and support the use of dynamic DNS services only for dedicated connections.

{{warning box|Pre-configured Dynamic DNS Service is no longer integrated into SME Server core functionality due to its rapidly changing providers. If you need this service, please refer to the "smeserver-dyndns" contrib.}}

Contribs.org has tested four dynamic DNS services, of which two are free services and two are commercial services: yi.org (free), dyndns.com (commercial), tzo.com (commercial) and dyndns.org (free). For simplicity, we have preprogrammed the server to work with these services (including pre-installing their client software). If you have arranged dynamic IP address assignment from your ISP and you wish to use one of these services, all you need to do is visit the appropriate web site to sign up for service, and enable that particular function in the server console. In pre-configuring the server for this particular service, we in no way interfere with nor prevent you from using another dynamic DNS service if you wish. To do so, however, would require some customized configuration on your part.

<!--Contribs.org has tested four dynamic DNS services, of which two are free services and two are commercial services: yi.org (free), dyndns.com (commercial), tzo.com (commercial) and dyndns.org (free). For simplicity, we have preprogrammed the server to work with these services (including pre-installing their client software). If you have arranged dynamic IP address assignment from your ISP and you wish to use one of these services, all you need to do is visit the appropriate web site to sign up for service, and enable that particular function in the server console. In pre-configuring the server for this particular service, we in no way interfere with nor prevent you from using another dynamic DNS service if you wish. To do so, however, would require some customized configuration on your part.

Contribs.org has tested the functionality of these services with our software. However, we accept no liability for any breach of service on their part. A failure on the part of your dynamic DNS service can result in your network becoming temporarily unreachable from the Internet. During these times, your e-mail may be undeliverable.

Contribs.org has tested the functionality of these services with our software. However, we accept no liability for any breach of service on their part. A failure on the part of your dynamic DNS service can result in your network becoming temporarily unreachable from the Internet. During these times, your e-mail may be undeliverable.-->

If your IP address is assigned dynamically and you intend to receive all your e-mail directly (rather than having it stored at an ISP and retrieving it via POP or IMAP), but you decide not to use a dynamic DNS service, you should implement multidrop e-mail as your e-mail solution as this will ensure that no e-mail is misdirected to another IP address (See Some important notes on Service list D (multidrop mail) in|Chapter 3.)

If your IP address is assigned dynamically and you intend to receive all your e-mail directly (rather than having it stored at an ISP and retrieving it via POP or IMAP), but you decide not to use a dynamic DNS service, you should implement multidrop e-mail as your e-mail solution as this will ensure that no e-mail is misdirected to another IP address (See Some important notes on Service list D (multidrop mail) in|[[SME_Server:Documentation:Administration_Manual:Chapter3#Service_List_D | Chapter 3]].)

{{Note box|Dynamic DNS services are not perfect. They merely point hostnames to IP addresses. If your system receives an IP address via DHCP or PPPoE, it will automatically update the dynamic DNS service each time it comes online. However, when your server disconnects from the Internet, with most dynamic DNS services your server does not indicate that it is offline in any way to the dynamic DNS service. If your system is offline for a period of time, it is possible that someone else will be assigned your IP address by your ISP. If this occurs, with most dynamic DNS services this other system will now start receiving your e-mail and web page requests until your server comes back online and updates the service with your new IP address. There is not much you can do about this, but you should be aware of this fact if there is any chance your system will be offline for a long period of time.}}

{{Note box|Dynamic DNS services are not perfect. They merely point hostnames to IP addresses. If your system receives an IP address via DHCP or PPPoE, it will automatically update the dynamic DNS service each time it comes online. However, when your server disconnects from the Internet, with most dynamic DNS services your server does not indicate that it is offline in any way to the dynamic DNS service. If your system is offline for a period of time, it is possible that someone else will be assigned your IP address by your ISP. If this occurs, with most dynamic DNS services this other system will now start receiving your e-mail and web page requests until your server comes back online and updates the service with your new IP address. There is not much you can do about this, but you should be aware of this fact if there is any chance your system will be offline for a long period of time.}}

=====DNS Service Providers=====

=====DNS Service Providers=====

Here is a brief list of vendors who provide DNS service hosting.  The inclusion of a vendor here does not constitute endorsement by the SME developers.

Here is a brief list of vendors who provide DNS service hosting.  The inclusion of a vendor here does not constitute endorsement by the SME developers.

* Dynamic DNS client included in SME 7.x:

*Dyndns.com   http://www.dyndns.com      $$$ (for 'Custom DNS' services)

*DuckDNS      https://www.duckdns.org/    $free

*Zoneedit    http://www.zoneedit.com    $free

** tzo.com     http://www.tzo.com          $$$

*FreeDNS      http://freedns.afraid.org  $free

** dyndns.com  http://www.dyndns.com      $$$ (for 'Custom DNS' services)

*EasyDNS      http://www.easydns.com      $19.95USD per year

 

* Other providers (dynamic DNS client not included in SME):

** Zoneedit    http://www.zoneedit.com    $free

** FreeDNS      http://freedns.afraid.org  $free

** EasyDNS      http://www.easydns.com      $19.95USD per year

====Appendix C. Proxy Servers====

====Appendix C. Proxy Servers====

If you are having difficulty configuring another vendor's hardware or software, we recommend you refer to the manual or contact the vendor for that product.

If you are having difficulty configuring another vendor's hardware or software, we recommend you refer to the manual or contact the vendor for that product.

The SME Server is open source software, Contribs.org encourages users to freely share copies of our software.

The SME Server is open source software, Koozali.org encourages users to freely share copies of our software.

Developers may wish to note that additional documentation, including HOWTO documents and a FAQ, can be found on our development web site - http://wiki.contribs.org/. There are also links there to other web sites relating to the server.

Developers may wish to note that additional documentation, including HOWTO documents and a FAQ, can be found on our development web site - http://wiki.koozali.org/. There are also links there to other web sites relating to the server.