Hello, I'm having trouble tracking down the root cause of an issue after a power outage. IMAP clients seem to fail connecting, despite services appearing to be running properly. SMTP inbound/outbound is working a-ok.
Here's some troubleshooting data gathered:
- WORKS: Carbonio Mail App
- WORKS: Carbonio webmail site
- FAILS: IMAP Clients (like Outlook, phone Mail apps)
Based on logs, it appears to be the internal IMAP Service running on `port 7143` not working:
==> nginx.log <== 2025/05/28 17:25:22 [error] 3506083#3506083: *32 recv() failed (111: Connection refused) while reading response from upstream, client: Y.Y.Y.65:60634, server: 0.0.0.0:993, login: "USEREMAIL" upstream: FQDN:7143 (Y.Y.Y.65:60634->X.X.X.25:993) <=> (10.10.Z.Z:48966->)
Services appear to be enabled, but it is peculiar that no service (per `netstat` is listening on that port):
$ zmprov gs `zmhostname` | grep zimbraService* zimbraServiceEnabled: service zimbraServiceEnabled: mailbox zimbraServiceEnabled: stats zimbraServiceEnabled: mta zimbraServiceEnabled: proxy zimbraServiceEnabled: directory-server zimbraServiceEnabled: antivirus zimbraServiceEnabled: memcached zimbraServiceEnabled: service-discover zimbraServiceEnabled: opendkim zimbraServiceEnabled: antispam zimbraServiceHostname: HOSTFQDN zimbraServiceInstalled: proxy zimbraServiceInstalled: memcached zimbraServiceInstalled: directory-server zimbraServiceInstalled: antivirus zimbraServiceInstalled: stats zimbraServiceInstalled: mailbox zimbraServiceInstalled: mta
$ sudo netstat -pnlt | grep 7143 <NOTHING>
zmcontrol -v Carbonio Release 25.3.1 zextras@mail:/home/USER$ zmcontrol status Host HOST antispam Running antivirus Running directory-server Running mailbox Running memcached Running mta Running opendkim Running proxy Running service webapp Running service-discover Running stats Running config service Running
What are some things to look at to ensure the IMAP service is running from here? I can't seem to find docs or relevant forum posts to help from here...
I can't look it up right now but secure IMAP 993 should be forwarded to unsecure IMAP 7143?
I thought 143->7143 and 993->7993, but I have never looked it up.
Maybe 993 is redirected to unsecure 7143 as internal security is not needed?
Is unsecured IMAP enabled on the server?
//Sigtrap
The assumption of 143 > 7143 and 993 > 7993 seems sound - and that's what our configuration has.
Double checking that 7993 Imap Server is running does show a process:
root@mail:/opt/zextras/log# netstat -plnt | grep 993 tcp 0 0 127.78.0.6:10000 0.0.0.0:* LISTEN 993/python3 tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 4115608/nginx: mast tcp 0 0 0.0.0.0:7993 0.0.0.0:* LISTEN 4102591/java
removed link also shows the Secure Imap Service start:
2025-05-29 16:40:53,266 INFO [main] [] imap - Starting ImapSSLServer on removed link
I do find another error that indicates a potential problem with the Imap Secure Service:
2025/05/29 18:25:23 [error] 4115610#4115610: *969 recv() failed (111: Connection refused) while reading response from upstream, client: x.x.x.x:21290, server: 0.0.0.0:993, login: "USER", upstream: FDNN:7143 (x.x.x.x:21290->y.y.y.y:993) <=> (z.z.z.z:38150->)
I'm wondering how to get logs directly from that service, or enable more verbose debugging logs. It appears those end up in removed link but a search of /opt/zextras/conf doesn't have any obvious loglevels to set. Any ideas on how to troubleshoot the backend service further?