Also, is the socks server at 172.xx.xx.xx accessible from your KumoMTA node? like can you NC ot telnet to it?
Im not sure I see a problem here. Source IP2 seems to be selected because it is the next one in the round-robin cycle.
I guess what you are saying is that the error is here due to the IPv6 Source 2 has a problem sending to the IPv4 destination:
Correct?
yes that’s correct
the socks server is on the same network as the mta node
and it totally makes sense that it’s the round-robin cycle
but, because i have to specify the socks5 source address, it will send a v4 MX to a source that i’ve defined as a v6 source address
and same the other way, v6 mx to a source that’s defined with a v4 source address
the way the documentation reads, i can’t leave out the socks5_proxy_source_address field and have the proxy figure it out
we’re doing a bigger full send tomorrow, so i can get you more data. My intuition says that in the current state of email there won’t be any domains that are only v6 only MX and hybrid v4/v6 domains with both published will work no issues
it’s the ones that are only v4 round-robin’ing to the v6 proxy source
@faithful-ostrich i can’t find an ipv6 example of the socks5 setup - does the socks5_proxy_source_address need to be formatted as a string or the ipv6 literal form? would it make a difference if it’s currently partially working?
like i would expect it fail with a config error if it wasn’t going to work
source address is always either an ipv4 or ipv6 address string. The config file won’t load if you put in an invalid address string
ok
hm, do you have any suggestions on a way to work around the issue we’re having then?
Source selection happens before we do MX resolution, so you cannot use the MX information to adjust the source.
However, you can configure source-specific options to skip eg: IPv6 or IPv4 addresses.
How do I skip IPv6 MX hosts for outbound SMTP? - KumoMTA Docs shows how to do this by default, but you can set up skip_hosts on a per source basis by setting skip_hosts when you build up your egress path config.
skip_hosts - KumoMTA Docs has very light docs showing lua vs. toml for this in general, but you can do something like this in your shaping.toml:
["example.com".sources."ip-1"]
skip_hosts = ["::/0"]
["example.com".sources."ip-2"]
skip_hosts = ["0.0.0.0/0"] # I didn't test this, but a v4 cidr should work here
gotcha
if we weren’t using socks5 would we avoid this issue or would it still rear its head
should we just not use ipv6?