I do not find any guidelines regarding how to configure multiple IPs into an SPF record. So far I used for example vspf1 ip4180. But now I. What to Check When Exchange Cannot Send Email to Certain DomainsTodays post comes to us courtesy of Shawn Sullivan Unable to send email to certain domains is a top call generator for Exchange issues on SBS. Due to its nature and the fact that all domains are not affected, the problem rarely lies with the SBS server. Several factors exist outside of the server configuration that can cause delivery failure to a remote mail server. PoSV55Eb33g/UEmmRLA93QI/AAAAAAAAALI/mEHTMCl-eXc/s1600/w2k_dns9.gif' alt='Create Spf Record Microsoft Dns Server' title='Create Spf Record Microsoft Dns Server' />This post is meant to be a quick guide to assist you in troubleshooting some common scenarios. It is not a comprehensive guide to SMTP troubleshooting. First of all, E SURE TO READ THE NDR. This is the most readily available piece of information that you have. It will tell you which mail server issued the notification and why, often leading you to the answer or at least in the right direction. One of the less well understood components of a working email system is the MX record. I do find a lot of IT administrators looking after Exchange servers who dont. How to Configure an SPF Record for Your Domain. Nowadays, there are various enterprise organizations that use domains that accommodate large amounts of users. Windows Server 2016 Editions. Microsoft has revealed two versions of Windows Server 2016 Datacenter Edition and Standard Edition. Here is a brief overview of each. Hello Im slightly confused. I have configured one of my hybrid servers with 0365. Sender Policy Framework SPF is a simple emailvalidation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to. The official blog for Windows Server Essentials and Small Business Server support and product group communications. In this article, lets have a look at setting up SPF record for Exchange on premise setup and Exchange hybrid setup. Why SPF Nowadays email domains over the internet. Managing DNS record sets and records on Azure DNS when hosting your domain on Azure DNS. All PowerShell commands for operations on record sets and records. Create Spf Record Microsoft Dns Server' title='Create Spf Record Microsoft Dns Server' />Who generates the NDR If the remote server accepts our message and then finds out after the fact that it cannot be delivered to the users mailbox, the remote server then must generate an NDR to notify the sender of the delivery failure. An example of this could be Your message did not reach some or all of the intended recipients. Subject test Sent 1. PM The following recipients could not be reached User. PMThe message could not be delivered because the recipients mailbox is full. If the remote server does not accept our mail, it will issue an SMTP error, at which point our SBS server is responsible for generating the NDR. The NDR will include the SMTP error code. Heres an example Your message did not reach some or all of the intended recipients. Subject test Sent 1. PM The following recipients could not be reached user. PMThe e mail account does not exist at the organization this message was sent to. Check the e mail address, or contact the recipient directly to find out the correct address. User unknown If the message sits in the queue because the SBS server cannot connect to the remote server, then SBS will issue an NDR according to the expiration timeout configured on the SMTP virtual server. An example of this could be Your message did not reach some or all of the intended recipients. Subject FW test Sent 1. AM The following recipients could not be reached user. AMCould not deliver the message in the time limit specified. Please retry or contact your administrator. SERVER1. This is important because the generation of NDRs by the SBS server does not automatically mean that the issue is with SBS. Determining possible causes of an NDRYou can view the following Technet link for NDR diagnostic codes and troubleshooting tips http technet. Common Scenarios. The following are common scenarios we see in support calls. As stated before, this list does not cover all possibilities, but provides a guide you can use to troubleshoot your incident. Blacklisting. If your server has been reported sending spam, either directly or through unauthorized relay, then your server is probably blacklisted. If so, you will need to take the appropriate steps to secure your environment and contact the individual block lists to be removed. Microsoft has no control over 3rd party blacklists. You can check your servers status in several places. Examples include http mxtoolbox. Some blacklists may block by entire IP address ranges. Your server may be included in the range. An alternative is to relay your companys email through a 3rd party provided smart host. Email for your domain will not originate from the blacklisted IP address. Connection Filtering. Your email domain or individual IP address may be explicitly blocked by the remote server without the use of online blacklists. You will need to contact that organization to find out why. You can relay mail through a smart host if available. Improper DNS resolution of Remote Server. It is possible that the remote domain is not blocking you at all, but that you are not even connecting to the correct server in the first place. You may be using a forwarder with a bad MX record for the remote domain. This can be configured in both the DNS management console under the server properties and on the SMTP virtual server properties in Exchange. You may be hosting an improper MX record for that domain i. DNS environment to hold itYou may have cached an invalid response. Flush your DNS cache and try again. Make sure that your hosts file is clean of invalid mappings to the remote server. You can verify the actual MX record for the remote domain by using http www. You determine the IP address you are trying to connect to either in the SMTP logs or through a netmon trace. Port 2. 5 blocked at the remote site. Maximum Transmission Unit MTU and Black hole Routers. A black hole router may exist between the SBS server and the remote mail server. If the SBS server is sending traffic that must be fragmented, but no ICMP control packet reaches SBS to let it know, then the traffic will be dropped without our knowledge. This can be proven with a simple ping test ping remoteserverip f l 1. For more information on using ping to test MTU, see http support. EN US 1. 59. 21. PTR Record. If the PTR record does not point your servers IP address to its properly registered name, certain organizations checking for this will drop your connection. If you are planning on hosting multiple email domains from the same Exchange server on a single public IP, make sure you are allowed by your ISP to have multiple PTR records for the same IP address. If not, then the domain missing the record may be blocked occasionally. PTR records are created by and typically maintained by your ISP. They own the IP address that you have been assigned and should be the first point of contact if you are having problems with a record. Unlike A records, PTR records are not hosted by your DNS registrar nor are they hosted by you even if you manage your own DNS namespace. Web sites you can use to check your PTR record include http www. Sender IDIf you are participating in the Sender ID Framework and have registered an improperly configured SPF Sender Policy Framework record, then you may be rejected by any mail server that checks this. If you are unsure of an existing SPF record or need to create a new one for your domain, visit the Sender ID Framework SPF Record Wizard http www. Grey Listing. Other Resources KB 2. Enhanced Status Codes for Delivery RFC 1. EN US 2. 56. 32. For SBS Monitoring Alerts not being delivered, see http blogs. For troubleshooting mail flow and transport related issues in Exchange, try the Exchange Troubleshooting Assistant http www. Family. ID4bdc. 1d. Display. Langen. The Microsoft Exchange Team Blog http msexchangeteam. How to set up a mail server on a GNU Linux system. Step by step guide to install Postfix. Ubuntu Postfix CourierDovecot IMAP My. SQL. Amavisd new Spam. Assassin Clam. AV. SASL TLS Roundcube Postgrey. Easy to follow howto on setting up a mail server. IMAP access, anti spam, anti virus. Based on an Ubuntu distribution platform. Examples are run on Amazon AWS ec. Respect CC by sa. Last Update 2. 01. Contents. Editions. Edition. State. Started. Updated. Description. Released outdated2. Based on Mandrake 9. Released outdated2. Based on Mandrake 1. Very thorough with advanced server sections. Released outdated2. Based on Ubuntu 5. Hoary Hedgehog. Now includes SASL TLS integration. Released outdated2. Based on Breezy Badger, Ubuntu 5. Includes Postgrey. Released outdated. Based on Ubuntu 6. LTS, Dapper Drake. Was to be based on Edgy Eft, Ubuntu 6. Domain Key signing. Released outdated. Updated, based on Ubuntu 8. LTS Hardy Heron. Using Amazon EC2 as example. Tested with 8. 1. Released outdated. Based on Ubuntu 8. Using official Ubuntu ec. Released outdated. Based on Ubuntu 9. Canonicals cloud images. Added Roundcube webmail option. Released outdated. Based on Ubuntu 1. LTS lucid using Canonicals cloud images. Tested on 1. 0. 1. Tested on 1. 1. 0. Based on Ubuntu 1. LTS precise. Tested with 1. Based on Ubuntu 1. LTS trusty. 2. 01. Based on Ubuntu 1. LTS trusty. Added Dovecot. Based on Ubuntu 1. LTS xenial. Further details available in the change log and below in the introduction. Introduction. Aim. This is a step by step howto guide to set. GNU Linux system. It is easy to follow, but you. The server accepts unlimited domains and users. It is secure, traffic can encrypted. Dont take my word for itResearch others opinions and methods. Look at my references. Postfix. orgs howtos. E. g. Kyles or Hildebrandts. If you refer to this howto in your own document. If you found this howto very useful, spread the word and help others If this howto was exceptionally useful why not donate me some beer money Or buy a postfix book using my Amazon affiliate links further down Or buy a t shirt from my t shirt shop Otherwise send me a Thank You note Bitcoin BTC 1. NUbs. Hd. 25oe. ZSUhwa. Pd. CQj. 9c. BHVwxhhhn. Ethereum ETH 0x. B7. A7. AA3. C8. E7b. F1. 84c. F1. 3Eb. E0cd. 4BC0. B2a. 0. Software. What software packages havewill I use and why. OS Ubuntu Linux. Ah the age old distro argument. Thankfully this set up should work on most distros. I used to base this howto on Mandrakenow Mandriva. I started this new edition on a Gentoo box. But I dont have the patience for Gentoo. Mandriva Power editions. Why Ubuntu Its free, simple and slick. As Ubuntu is derived from debian the installations. Please refer to my other editions for details on RPM. MTA Postfix. Simple, free and slick. Yup I am a sucker for anything that works easily. Postfix is powerful, well established. PopIMAP Courier IMAP or Dovecot. My first mail server installation was with Courier. I have not found a reason to change this as again. A popular alternative, is Dovecot. Database My. SQL. Although I use Firebird for my application development. HibernateC JDBC hybrids. My. SQL is well supported for the sort of lookups required. Content Check Amavisd new. Easy plug in solution for spam, virus checking etc. Anti Spam Spam. Assassin. Hank Rar Sr Williams. Powerful renowned spam fighting tool. Anti Virus Clam. AV. Free virus scanner that can be trusted and includes update daemon. Authentication Cyrus SASL. Secure and trusted cryptography technology. SMTP traffic. Postgrey is an excellent little script to stop 9. All it does is on first contact for specific from to combinations. When proper servers try again after a few minutes it lets it through. Encryption TLS. Secure and trusted cryptography technology. SMTP traffic. Not too be confused with client encryption technology. Gnu. PG and SMIME. They are covered in the. Formerly referenced as SSL. Web. Mail Squirrel. Mail or Roundcube. Easy to set up php based web mail client. Extensive plugin selection. Ajaxified prettier web mail client. Not quite as solid as Squirrel. Mail. Platform Amazon ec. This guide can be installed locally, co located or in the cloud. My preference is ec. I provide ec. 2 based examples. Please see software links appendix for further information. In that section there is more links to. Further software and tweaks are discussed in the. Also review other peoples opinion on these packages via my references. Installation. Distribution. This section is different for every distribution and for every version. This howto is based on Ubuntu and its base of debian which uses apt get. Therefore this section uses apt packages to its fullest. For other installation method please refer to previous editions. My 2nd editionoutdated has instructions. Mandriva, general RPM and tarball compiling. To follow the rest of this howto with another distribution. E. g My. SQL lookup on postfix and sasl, php in apache etc. I have set up mail servers using the 3. E. g. Mac platforms should work too. With installing Ubuntu you have a choice of which base system to install. You may choose server or desktop image or very basic setups. I will assume a server install, but it should not differ. If you have chosen an ec. I strongly suggest choosing the latest LTS version of Ubuntu, not the versions in between. Once this is set up you will tinker very little with it, and it will quickly be annoying to upgrade distributions once a year. Ps. Please note that after a while Ill stop specifying the use of sudo. My advice is to use sudo. For assistance with repositories, refer to this article on ubuntus wiki. I would recommend find a repository archive close to your servers location. For example a country specific one or if hosted on AWS EC2 an archive in your AWS region. Remember these are highly security sensitive so choose one you trust. You need the main and universe repositories. The multiverse, restricted and partner can be added but are not needed. Do not add backports. Uncomment the lines that have commented out universe. E. g. here are mine for ec. Europe. deb http eu west 1. Note the security repository always have to go to the non mirrored server. As mentioned in the previous edition. You need to install a whole bunch of packages. We will install them bit by bit. But first check your package sources are correctly pointing to main multiverse restricted universe. Ubuntu version. sudo vi etcaptsources. Secondly update your current system. Note aptitude is no longer supplied in the base install of Ubuntu. This is due to some concurrency issues. Some part of this document may still refer to aptitude. You should use the original apt get instead. Additional packages. I also install a few other packages that I personally prefer. But nothing todo with the mail server. Mutt is a very usefull command line mail client that I always install. I usually do that at the end when testing so that it doesnt. Postfix before I am ready. Package status. To find out which packages you may have installed. And to find which are available. Configuration. Simple mail server. Now lets configure a simple mail server using some of. Firewall. Shorewall. Not essential for an EC2 image. It is essential for a normal server. UFW is bundled with recent Ubuntu distributions. I still prefer Shorewall for servers. Installationsudo apt get install shorewall shorewall doc. Amazon provides a firewall access control for its servers. And in all others situations a must have.