On 1/11/2011 12:24 AM, Noel Jones wrote:
On 1/10/2011 11:13 PM, Ramesh wrote:
Hi,
I have few queries about changing mail priority level. presently we
have taking mail service from mail service provider, we want to bring
up our own mail server as primary.
mx entries
example.com mail is handled by 0 example.com.
example.com mail is handled by 10 mailhub.example.com.
Yesterday i've changed priority 0 to 20, making mailhub as lowest
priority 10, primary mail server for example.com
when i send mail to x...@example.com from yahoo
maillog in mailhub shows 554 5.7.1 (Relay access denied) but i can
send mail from mailhub through webmail.
"relay access denied" means that example.com is not listed in
mydestination, virtual_domains, virtual_alias_domains, or
relay_domains. Postfix doesn't think it's responsible for that domain.
I would like to know...
1)If we change mx priority, how much time it will take to update
priority level?
Depends on your DNS TTL and if the remote site has your records
cached. Anywhere from a couple minutes to a couple weeks for sites
that have the old records cached. No delay for sites that don't have
your records cached.
2)If it takes more time during this period where new mails queued?
Mail will be sent to the old primary if that's what remote sites have
cached.
Please suggest me things to follow for migrating primary to secondary
mail server.
It's customary to reduce your DNS TTL a few days prior to planned
changes.
Thanks and Regards,
Ramesh
-- Noel Jones
I dont think this guy understands time to live or dns and how they
correlate.
The time to live is the offset between the server and the client
requesting the dns lookup. This offset is used in calculating the
expire, refresh, and transfer times; these tell the client what interval
it should USUALLY update to see if there is a record change, the refresh
time, and the MAXIMUM time any client should wait before considering its
cache stale, the expiry time. The transfer is use for slave dns servers,
to know how often they should refresh.
With this in mind, whatever your refresh time contains is how long all
resolvers will wait before looking at your new mx record. This is the
reason noel said to decrease the refresh and expiry times, presumably to
64 seconds, a couple days, or a day at least, before you change them;
so, that the servers that resolve the day before will check back more
frequently to see if you change it. The default refresh and expiry is 2
- 3 days; which now means your change, on mail transports that resolved
your mx within the last 2 days, will not be in effect for 36 hours at
least and 72 hours at most.
Jerrale G.
SC Senior Admin
