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Community Member

Outbound relay #2

We have Vigor 2820 router with NAT for multiple public static ip addresses  - unfortunately we are unable to setup reverse DNS on the main public ip range - only the original static ip address has rdns configured; so in order to ensure emails get passed when the remote end checks for rdns  - we need to ensure that the outbound relay traffic from csvb is presented on the correct outbound listener.

AFAIK I have correctly configured both the initial public listener (works) and subesquently setup a private listener (also works) to try a different private/natted public ip address; and unfortunately  - email header logs appear to show outbound email still going via the public range that has no rdns. As far as I can see it - both the original private ip addresses had 1-1 mapping with the "good" public ip address - so I am rather bemused.

I am pretty sure it must be a port forwarding/router issue; but wondered if anyone can shed some light on the outbound relay mechanism using csvb. I am deducing that the email is relayed via direct DNS lookup on the remote end's mx records and does not go via any great relay data centre/cloud in the sky on its way to the end point?

Anyone have any ideas for proving the point from a csvb perspective?

TIA Paul Mead.

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Community Member

Re: Outbound relay #2

Paul - you answered your questions yourself :) The CSVB uses dns mx records to understand where to route mails to for non-local domains not referenced in the smtproutes table.

Of course - if you wanted to relay all outbound mail to an upstream relay then use the 'ALL' for the default route. Any non-local route will follow this route instead.

jason

See what it would look like from the CLI:

(Machine spam.fli.org)> smtproutes

There are currently 97 routes configured.

Choose the operation you want to perform:
- NEW - Create a new route.
- EDIT - Edit destinations of an existing route.
- DELETE - Remove a route.
- PRINT - Display all routes.
- IMPORT - Import new routes from a file.
- EXPORT - Export all routes to a file.
- CLEAR - Remove all routes.
- CLUSTERSET - Set how SMTP routes are configured in a cluster.
- CLUSTERSHOW - Display how SMTP routes are configured in a cluster.
[]> new

Enter the domain for which you want to set up a permanent route.
Partial hostnames such as ".example.com" are allowed.
Use "ALL" for the default route.
[]> ALL

Enter the destination hosts, separated by commas, which you want mail for ALL
to be delivered.
Enter USEDNS by itself to use normal DNS resolution for this route.
Enter /dev/null by itself if you wish to discard the mail.
Enclose in square brackets to force resolution via address (A)
records, ignoring any MX records.
[]> 1.1.1.1

Default route updated.

There are currently 98 routes configured.

3 REPLIES
Community Member

Re: Outbound relay #2

I suppose the other way of resolveing it  would be to force cvsb to smart relay the outbopund email to a preferred realy rather than letting is perform direct dns mx relay? Is this possible -it would be another way round this issue. PLM

Community Member

Re: Outbound relay #2

Paul - you answered your questions yourself :) The CSVB uses dns mx records to understand where to route mails to for non-local domains not referenced in the smtproutes table.

Of course - if you wanted to relay all outbound mail to an upstream relay then use the 'ALL' for the default route. Any non-local route will follow this route instead.

jason

See what it would look like from the CLI:

(Machine spam.fli.org)> smtproutes

There are currently 97 routes configured.

Choose the operation you want to perform:
- NEW - Create a new route.
- EDIT - Edit destinations of an existing route.
- DELETE - Remove a route.
- PRINT - Display all routes.
- IMPORT - Import new routes from a file.
- EXPORT - Export all routes to a file.
- CLEAR - Remove all routes.
- CLUSTERSET - Set how SMTP routes are configured in a cluster.
- CLUSTERSHOW - Display how SMTP routes are configured in a cluster.
[]> new

Enter the domain for which you want to set up a permanent route.
Partial hostnames such as ".example.com" are allowed.
Use "ALL" for the default route.
[]> ALL

Enter the destination hosts, separated by commas, which you want mail for ALL
to be delivered.
Enter USEDNS by itself to use normal DNS resolution for this route.
Enter /dev/null by itself if you wish to discard the mail.
Enclose in square brackets to force resolution via address (A)
records, ignoring any MX records.
[]> 1.1.1.1

Default route updated.

There are currently 98 routes configured.

Community Member

Re: Outbound relay #2

Thanks for the thorough response. I have good news - with some great support from Vigor here in the UK we were able to resolve the public routing issue outbound (sort of outbound round robin mechanism for multiple public ip addresses - removed the public address with no rdns from the NAT pool and all is wonderful) - so easy when you fully appreciate the tick box setting (was not quite what I though it did!). Duh from me - only been using the kit for about 6 years+

Impressed that CSVB is able to in effect perform upstream mail relay as indicated by your answer - I think I understand how one would do this via the front end interface from your answer. I suspect that SMB clients are more likely to want to perform this than let CSVB perform its own relay - if only to help improve its own "reputation score" via their ISP or 3rd party relay provider. Anybody want to add their opinion?

Many thanks.

Paul.

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