Is there a way to avoid using IPv6 in outgoing SMTP connections?

Hi, I have issues sending email using ipv6 because my VPS provider (OVH) allocates a single ip /128 to each vm, and of course a lot of neighbor addresses (inside the /64) are in blacklist, so I'm in blacklist too. This is a known problem since forever but they just don't fix it. It would require a major overhaul of the v6 allocations for the whole infrastructure.

The obvious solution is to not use ipv6 for SMTP sending (but I can use it for receiving, no problem there).

So I tried to set "interface = MY V4 ADDRESS" in the smtp transport config.

It does not work, it still uses both v4 and v6.

 From what I have understood from documentation, it's by design, it's not a bug. If I select a v4 address and not a v6 address, the logic of address selection will happily use the first available v6 address because I have not chosen a specific v6 address to use.

This takes me to the point: is there no way of telling Exim to use only ipv4 in outgoing smtp connections, apart from disabling v6 completely in Exim (with disable_ipv6=true), thus rejecting also incoming v6 smtp connections?

Thanks.


-- 
Fabio Muzzi

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