No SPF record on `mail.nixosdiscourse.fcio.net`

1

I am probably one of the few people that use mailing list mode feature, but it seems e-mails from this discourse forum have stopped in November 2025.

Upon initiating the confirmation e-mail process, I observe this messages in logs:

Jan 24 16:08:02 mail bash[487454]: mail-1      | 2026-01-24T16:08:02Z INFO SMTP EHLO command (smtp.ehlo) listenerId = "smtp", localPort = 25, remoteIp = 185.105.252.151, remotePort = 58588, domain = "mail.nixosdiscourse.fcio.net"
Jan 24 16:08:02 mail bash[487454]: mail-1      | 2026-01-24T16:08:02Z INFO SPF EHLO check failed (smtp.spf-ehlo-fail) listenerId = "smtp", localPort = 25, remoteIp = 185.105.252.151, remotePort = 58588, domain = "mail.nixosdiscourse.fcio.net", result = No SPF record (spf.none), elapsed = 36ms

Confirmed with:

$ dig TXT mail.nixosdiscourse.fcio.net

; <<>> DiG 9.20.17 <<>> TXT mail.nixosdiscourse.fcio.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 19711
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;mail.nixosdiscourse.fcio.net.  IN      TXT

;; AUTHORITY SECTION:
fcio.net.               300     IN      SOA     ns3.fcio.net. support.flyingcircus.io. 1723719336 10800 60 1209600 300

It’s defined in discourse.nixos.org:

$ dig TXT discourse.nixos.org

; <<>> DiG 9.20.17 <<>> TXT discourse.nixos.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17780
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;discourse.nixos.org.           IN      TXT

;; ANSWER SECTION:
discourse.nixos.org.    3200    IN      TXT     "v=spf1 ip4:185.105.252.151 ip6:2a02:248:101:62::1479 -all"

;; Query time: 13 msec
;; SERVER: 100.100.100.100#53(100.100.100.100) (UDP)
;; WHEN: Sat Jan 24 10:30:47 CST 2026
;; MSG SIZE  rcvd: 118

But not on the DNS name returned by MX on discourse.nixos.org:

$ dig MX discourse.nixos.org

; <<>> DiG 9.20.17 <<>> MX discourse.nixos.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29906
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;discourse.nixos.org.           IN      MX

;; ANSWER SECTION:
discourse.nixos.org.    2314    IN      MX      10 mail.nixosdiscourse.fcio.net.

;; Query time: 13 msec
;; SERVER: 100.100.100.100#53(100.100.100.100) (UDP)
;; WHEN: Sat Jan 24 10:31:46 CST 2026
;; MSG SIZE  rcvd: 92
2

I contacted support@flyingcircus.io; they say they’ll have a look at this.

1 Like
3

fyi: this might be a non-issue. May have been a bug in my mail server software. I updated the software and I am able to receive mails from this discourse.

1 Like
4

Thanks for the update. I also suspected that something unusual was happening on the receiving mail server, as this was the first report about the issue. It would be interesting to learn what software you updated, could you share?

5

hey @dpausp – I was running an instance of Stalwart (v0.11.x) on a Debian machine in a OCI container (docker).

Decided to upgrade to the latest (0.15.4), migrate it and data to a NixOS machine, and manage it declaratively using the services.stalwart-mail.* options.

1 Like