Dear ALL
I have the following setup running good for quite sometime and i wd really apprecite if someone wd help or give some suggestions
centos 5.1 sendmail dns server
now recently our mail usage has increased considerably and moreover Mails have become a utmost top priority
i have 2 options now
1) have a backup server with lower higher MX
i tested this setup n had some queries earlier n thanks to guys like scott for some prfect advise i did manage to check it out n it works beautiful
2) have another server with same value of MX so it cd load balance and also doc says if one server is down or unavaliable the oher server would receive mail
now my query is ... if i now configure a second mail server with same MX priority .
a) do i have to create all the existing user accounts on my existing email server to this new server cause i already hav about 300+ email users already
b) incase my first email server fails are the emails on the first server lost
c) alos apprecite if someone can help me with any links or docs for the above setup
apprecite and really thnks in advance
regards Fabian
fabian dacunha wrote:
a) do i have to create all the existing user accounts on my existing email server to this new server cause i already hav about 300+ email users already
Depends what you want to accomplish, for the simplest of setups, no. You can (depending on the MTA of course), simply route all mail for a particular domain or host name to another system.
In postfix this is accomplished like this: (snip the usual basic config) transport_maps = hash:/etc/postfix/transport local_recipient_maps = proxy:unix:passwd.byname, $alias_maps, hash:/etc/postfix/local_recipient
then in /etc/postfix/local_recipient: @mydomain.com THIS VALUE MUST BE PRESENT BUT IS IGNORED
and in /etc/postfix/transport: mydomain.com smtp:name_of_other_smtp_server
run postmap hash:/etc/postfix/local_recipient run postmap hash:/etc/postfix/transport restart postfix and off you go.
If you want to reject mails for invalid users at the backup MX then you can probably put the user names in the local_recipient file above, create the accounts on the system, or use a distributed authentication database like SQL, LDAP etc. My preference is the above blind forward method, if the user is invalid then the server will reject it, I don't care if it sits in the queue for a few days on the backup system.
b) incase my first email server fails are the emails on the first server lost
Depends on what you mean by fail and depends if the mail on the first server is stored there or if that system simply forwards on to another host for delivery to users. If the users that read mail access it from that system, and that system bursts into flames, and the mails happen to sit on internal storage inside the system(as opposed to a NAS or a SAN) then yes mail stored on that system is lost. If the system simply crashes and needs to be rebooted then it is likely nothing is lost.
nate
On Wed, Jul 16, 2008, fabian dacunha wrote:
Dear ALL
I have the following setup running good for quite sometime and i wd really apprecite if someone wd help or give some suggestions
centos 5.1 sendmail dns server
now recently our mail usage has increased considerably and moreover Mails have become a utmost top priority
i have 2 options now
- have a backup server with lower higher MX
i tested this setup n had some queries earlier n thanks to guys like scott for some prfect advise i did manage to check it out n it works beautiful
- have another server with same value of MX so it cd load balance and
also doc says if one server is down or unavaliable the oher server would receive mail
now my query is ... if i now configure a second mail server with same MX priority .
Having multiple servers with the same MX priority works fine (I prefer to think of this as distance as the lower ones have higher priority). There's no good reason to have multiple distances other than the shortest for final delivery and one or more with higher in case the primary is not available for some reason.
a) do i have to create all the existing user accounts on my existing email server to this new server cause i already hav about 300+ email users already
No, the secondary MX server(s) don't need any user accounts. Using postfix, we do generate a virtual file for each secondary MX server containing all the valid addresses for the domain(s) served by the primary server, allowing the MX servers to reject invalid accounts without having real user accounts.
There are some good arguments for having a single MX server rather than multiple MX servers as it prevents spammers from attempting to deliver mail through the higher distance MX servers which may well not have the same anti-spam rules. At one of our regional ISP customers with about 10,000 e- mail accounts, we use a single MX server to accept incoming messages, This server runs postfix, amavisd-new, and clamav to pre-screen incoming messages for worms (Windows is the Virus) and phishing messages, then it forwards clean messages to a cluster of systems that do spamassassin checking and message delivery to the user's Maildir message stores which are NFS mounted on a central server.
The MX server in this case rejects about 2,000,000 messages a day using a variety of IP filters, and delivers about 250,000 messages a day. It has a load average less than 1.00 except during the daily maintenance and security audits.
It actually is the primary MX server for two distinct groups of domains, each with a separate user base. Each machine that is home to the user's home directories updates its own section of the postfix virtual table, using rsync to update the MX server whenever anything changes with the users. The MX server uses the postfix transport file to direct mail to the appropriate cluster servers to deliver mail.
Bill
Thanks guys for the immediate reply..
anyway based on your nice sugeestions i feel that having a mail server with different MX records would be definately better than having 2 servers with the same MX since i was confused about which setup to be used
setting up 2 server with same MX or one with higher n one with lower priority
thnks once again
regards
fabian
On Wed, Jul 16, 2008, fabian dacunha wrote:
Dear ALL
I have the following setup running good for quite sometime and i wd really apprecite if someone wd help or give some suggestions
centos 5.1 sendmail dns server
now recently our mail usage has increased considerably and moreover Mails have become a utmost top priority
i have 2 options now
- have a backup server with lower higher MX
i tested this setup n had some queries earlier n thanks to guys like scott for some prfect advise i did manage to check it out n it works beautiful
- have another server with same value of MX so it cd load balance and
also doc says if one server is down or unavaliable the oher server would receive mail
now my query is ... if i now configure a second mail server with same MX priority .
Having multiple servers with the same MX priority works fine (I prefer to think of this as distance as the lower ones have higher priority). There's no good reason to have multiple distances other than the shortest for final delivery and one or more with higher in case the primary is not available for some reason.
a) do i have to create all the existing user accounts on my existing email server to this new server cause i already hav about 300+ email users already
No, the secondary MX server(s) don't need any user accounts. Using postfix, we do generate a virtual file for each secondary MX server containing all the valid addresses for the domain(s) served by the primary server, allowing the MX servers to reject invalid accounts without having real user accounts.
There are some good arguments for having a single MX server rather than multiple MX servers as it prevents spammers from attempting to deliver mail through the higher distance MX servers which may well not have the same anti-spam rules. At one of our regional ISP customers with about 10,000 e- mail accounts, we use a single MX server to accept incoming messages, This server runs postfix, amavisd-new, and clamav to pre-screen incoming messages for worms (Windows is the Virus) and phishing messages, then it forwards clean messages to a cluster of systems that do spamassassin checking and message delivery to the user's Maildir message stores which are NFS mounted on a central server.
The MX server in this case rejects about 2,000,000 messages a day using a variety of IP filters, and delivers about 250,000 messages a day. It has a load average less than 1.00 except during the daily maintenance and security audits.
It actually is the primary MX server for two distinct groups of domains, each with a separate user base. Each machine that is home to the user's home directories updates its own section of the postfix virtual table, using rsync to update the MX server whenever anything changes with the users. The MX server uses the postfix transport file to direct mail to the appropriate cluster servers to deliver mail.
Bill
INTERNET: bill@celestial.com Bill Campbell; Celestial Software LLC URL: http://www.celestial.com/ PO Box 820; 6641 E. Mercer Way Voice: (206) 236-1676 Mercer Island, WA 98040-0820 Fax: (206) 232-9186
People from East Germany have found the West so confusing. It's so much easier when you have only one party. -- Linus Torvalde, Linux Expo Canada when asked about confusion over many Linux distributions. _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
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on 7-16-2008 12:42 AM fabian dacunha spake the following:
Thanks guys for the immediate reply..
anyway based on your nice sugeestions i feel that having a mail server with different MX records would be definately better than having 2 servers with the same MX since i was confused about which setup to be used
setting up 2 server with same MX or one with higher n one with lower priority
thnks once again
Just remember to have adequate spam and virus scanning on the backup MX also. Because it will be hammered with most of the junk eventually.
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Bill Campbell -
fabian dacunha -
nate -
Scott Silva