Change HELO-fqdn for cluster gateways

Greg_88

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May 22, 2019
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Hello everyone,

My topics (and problem) is smiliar to https://forum.proxmox.com/threads/change-helo-fqdn-independently-from-server-hostname.44186/ and https://forum.proxmox.com/threads/change-helo-hostname.52582/.
We want to change our Helo name to something different then our hostname of proxmox. The reason is that some mailservers who force Helo check are blocking our e-mails currently they see our internal hostname of proxmox server (identical problem as second topic).

We have two gateways (on cluster) where we cannot change a smtp_helo_name for these machnies.
When we change a smtp_helo_name, cluster system after synchronization overwrites the values, and this way we back to the start position. I've introduced a changes directly in file /etc/postfix/main.cf but this way system overwrites the values.

We use a version 5.1-4 Proxmox Gateways.
 

Stoiko Ivanov

Proxmox Staff Member
Staff member
May 2, 2018
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hmm - could you provide a bit more details - what is your current hostname on the systems (if you want, pseudonymize the domains)? and what do you want to set smtp_helo_name to for each node?

I assume you already copied the main.cf.in template from /var/lib/pmg/templates to /etc/pmg/templates (if not please see https://www.proxmox.com/images/download/pmg/docs/pmg-admin-guide.pdf - section 4.3)
(you can use a few variables in the templates, e.g. the hostname)

Hope this helps!
 

Greg_88

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May 22, 2019
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Thank you for response.

I've read about copy main.cf.in template from /var/lib/pmg/templates to /etc/pmg/templates, but I did not do it. I make a test for 2-3 houres (unfortunatelly on production system). Of course i give you sign about results this operation.

We must remember that file/files from /etc/pmg/templates will be automatically synchronized to the second gateways. What will happen if the second gate has a different address?

For more details I decribe a technical situation :

We have :
- mailserver
- first proxmox gate: aaaa1r (hostname: gw1r)
- second proxmox gate: bbbb2cz (hostaname: gw2cz)
Gatways are working as cluster (active - passive).

External DNS for:
- first proxmox gate is: example3.mail.xxx on 10.10.12.201
- second proxmox gate: example2.mail.xxx on 10.10.55.202
(fiction domain and IP's)


and on this point I would like back to my question form this post: What will happen if the second gate has a different address?
What will happen when we set variable "hostname = example3.mail.xxx" on first proxmox gate? According to the guide (point 4.3 from your link) data will be synchronizred automatically.
In this situation the second gateway will be not working.

I make a test and give you sign.
 

Stoiko Ivanov

Proxmox Staff Member
Staff member
May 2, 2018
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not sure i understood your examples completely are 'aaaa1r' and 'bbbb2cz' the hostnames? domainnames?
In any case since it seems that your 'external' hostname (and the one you want to set as smtp_helo_name don't match any part of the internal names you probably will need to use the templating mechanisms for the config - roughly like this:
Code:
[% IF dns.hostname == 'gw1r' %]
smtp_helo_name = example3.mail.xxx
[% ELSE %]
smtp_helo_name = example2.mail.xxx
[% END %]

you can see the variables you can use in the if clause with `pmgconfig dump`

the template toolkit (which is used for the config-file templates) documentation can be found at http://www.template-toolkit.org/docs/modules/Template.html

hope this helps!
 
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Greg_88

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May 22, 2019
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ok I understand that I have to copy the file main.cf.in from the location /var/lib/pmg/templates to the location /etc/pmg/templates/

The only question is whether in this file I have to leave only the configuration that I want to change or the entire file to copy as it flies because I do not understand how this file works. How do I copy this file, it will not overwrite the current settings that I already have?

This solution you gave looks good.

So this file (main.cf.in) must be completely copied with the configuration that is contained in it? Can I clean it and add only the variable that interests me, such as your example?
 

Stoiko Ivanov

Proxmox Staff Member
Staff member
May 2, 2018
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So this file (main.cf.in) must be completely copied with the configuration that is contained in it?
yes - this file is used to generate your '/etc/postfix/main.cf' - only what is written in this file is written in '/etc/postfix/main.cf'

you can make a backup of your current config, edit the template, run `pmgconfig sync` and compare both files (the new '/etc/postfix/main.cf' and the backup you made)
 
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Greg_88

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May 22, 2019
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Thank you for your help and guidance on the solution.
I've made changes to my gates and it works as I assumed.
 
Jul 19, 2019
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This is what I did to make sure each cluster node presents itself to the outside with the correct name:

[% IF dns.hostname == '<server1>' %]
myhostname = mx1.domain.nl
[% END %]
[% IF dns.hostname == '<server2>' %]
myhostname = mx2.domain.nl
[% END %]
 

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