Re: avoiding overload on port 587
- Am 01.12.2012 02:21, schrieb Stan Hoeppner:
> On 11/30/2012 6:08 PM, Wietse Venema wrote:it is no problem with linux on ESXi
>> Stan Hoeppner:
>>> That said, given the ongoing clock issues that all the guest/hypervisor
>>> combos have always experienced to some degree, and will forever
>>> experience no matter how good the mitigation hacks, it is my opinion,
>>> and Wietse's, and many others, that mail is not really a suitable
>>> application for most virtual environments. I'm sure you'll now write at
>> Um, I have pointed out failures. I do not claim that all virtualization
>> environments fail to meet the requirements
> My apologies for the mis-attribution Wietse. I agree not all virtual
> environments have clock problems serious enough to avoid deploying mail
> servers. I stated "most", which may likely be better described today as
> "many". It's still a problem with Linux on ESX though not as bad as it
> once was
"divider=10 clocksource=hpet" with current ESXi5 und HW8
but i have running since 2008 a lot of virtual machines and since
2009 two mailservers with postfix and even without "clocksource=hpet"
which is bot supported in virtual hwardwre below v8 there wo NO timedrift
at all, a "distribute-command.sh date" shows the same time on any machine
in the list independent on which host or phsyical or even on
what location it is running
so if time drift is your only problem with virtualization there
is no problem at all at least with recent fedora guests and RHEL6
- On Tue, Dec 04, 2012 at 07:46:10AM -0600, /dev/rob0 wrote:
> On Tue, Dec 04, 2012 at 11:59:01PM +1300, Peter wrote:Or better yet: replace it with postscreen.
> > I would still also set up port 587 on the mail.example.com
> > IP as submission as well and try to encourage your users (at
> > least the ones you can) to use port 587 from now on.
> What I would do, on Linux with IPv4 only, is create the submission
> port and use an iptables redirect for the alternate IP address:
> # iptables -vt nat -A PREROUTING -p tcp --dport smtp -d \
> mail.example.com -j REDIRECT --to-port submission
> This saves the overhead (system and administrative) of running
> another smtpd on [mail.example.com]:25; he can leave his "smtp ...
> smtpd" service alone in master.cf.
> I should also add as a reply to Stan in the other subthread: lookTo clarify, I meant that if those Outlook Expresses are not yet
> above at the first quoted paragraph: "Outlook Expresses setup with
> ... default configuration."
> Yikes, bad news, very bad. If not doing content filtering nor
> policy limitation of submission now, he will be soon. And possibly
> losing his job in any case. Tomas is not in a good place right now.
compromised by malware, they will be, soon.
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