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?
Any additional thoughts on how to troubleshoot this? We dug in a little deeper but nothing seems to connect to the backend service properly.
Any other ideas on what to troubleshoot? It appears the right service is running, but there's bad communications between it. Nothing detailed in the logs that we can find to indicate what it is.