Hi all,
I'm working on replacing our old 4.0 setup with the 7.4. We are taking this opportunity to review and recreate our monitors. I'm including my troubleshooting info below, I used ai to format my notes a bit better for readability.
We are going from a single instance, to a proxied setup. This is a fresh install with no existing configuration being migrated. We have our primary server offsite with an IPSec tunnel to the network on our proxy is on. I can hit ping and hit zabbix ports from server to proxy and agent to proxy. Testing both ways. Although, there does seem to be anomolies when data is sent from server to proxy. Like the data is truncated?
We've monitored router and firewall logs, nothing is getting blocked, and looks like proxy is breaking connection cleanly. Not really getting any logs indicating the issue.
General Info:
Zabbix Primary Server - Offsite (a.a.a.a) IPSec tunnel to the network proxy is on
Zabbix Proxy Server - Located in our network (b.b.b.b)
Agent - Same network as proxy (c.c.c.c)
Agent
Agent connectivity
• Agent can ping and reach proxy port (logs available).
• Hostname=DEV-HTSM confirmed — matches exactly in Zabbix UI (verified in hex).
• Server=b.b.b.b,127.0.0.1 — proxy and localhost defined.
• SourceIP=c.c.c.c — matches expected value.
• TLS/Encryption fully disabled for testing:
TLSConnect=unencrypted, TLSAccept=unencrypted
• Everything on the agent side checks out — likely not the issue.
Proxy
Listening ports:
tcp LISTEN 0 4096 0.0.0.0:10051
tcp LISTEN 0 4096 [::]:10051
SELinux rules:
zabbix_agent_port_t tcp 10050
zabbix_port_t tcp 10051,10051
Connectivity:
nc -vz a.a.a.a 10051 → OK (to primary)
nc -vz c.c.c.c 10050 → OK (to agent)
Proxy details:
• ProxyMode=0 (Active)
• Server=a.a.a.a (Primary)
• Hostname= zabbixproxy.test.com
• Local DB configured:
DBHost=localhost, DBName=zabbix_proxy
• Timeout=30
• Unencrypted: TLSConnect=unencrypted, TLSAccept=unencrypted
• Verified startup log:
Primary Server
Connectivity:
nc -vz b.b.b.b 10051 → OK (to proxy)
Listening ports:
tcp LISTEN 0 4096 0.0.0.0:10051
tcp LISTEN 0 4096 0.0.0.0:10050
tcp LISTEN 0 4096 [::]:10051
tcp LISTEN 0 4096 [::]:10050
Database → zabbix-db.test.com
• Connection + writes working fine.
• Timeout=4s (default 3s — likely fine).
• Server can ping and connect to both proxy and DB.Observed behavior:
| proxyid | name | operating_mode | description | tls_connect | tls_accept | tls_issuer | tls_subject | tls_psk_identity | tls_psk | allowed_addresses | address | port | custom_timeouts | timeout_zabbix_agent | timeout_simple_check | timeout_snmp_agent | timeout_external_check | timeout_db_monitor | timeout_http_agent | timeout_ssh_agent | timeout_telnet_agent | timeout_script | local_address | local_port | proxy_groupid | timeout_browser |
| 6 | zabbixproxy.test.com | 0 | | 1 | 1 | | | | | b.b.b.b | b.b.b.b | 10051 | 0 | | | | | | | | | | | 10051 | NULL | |
tcpdump findings:
Primary server sends configuration; proxy receives data, but payload sizes differ slightly — possible truncation or early termination during config transfer.
I'm working on replacing our old 4.0 setup with the 7.4. We are taking this opportunity to review and recreate our monitors. I'm including my troubleshooting info below, I used ai to format my notes a bit better for readability.
We are going from a single instance, to a proxied setup. This is a fresh install with no existing configuration being migrated. We have our primary server offsite with an IPSec tunnel to the network on our proxy is on. I can hit ping and hit zabbix ports from server to proxy and agent to proxy. Testing both ways. Although, there does seem to be anomolies when data is sent from server to proxy. Like the data is truncated?
We've monitored router and firewall logs, nothing is getting blocked, and looks like proxy is breaking connection cleanly. Not really getting any logs indicating the issue.
General Info:
Zabbix Primary Server - Offsite (a.a.a.a) IPSec tunnel to the network proxy is on
Zabbix Proxy Server - Located in our network (b.b.b.b)
Agent - Same network as proxy (c.c.c.c)
Agent
Agent connectivity
• Agent can ping and reach proxy port (logs available).
• Hostname=DEV-HTSM confirmed — matches exactly in Zabbix UI (verified in hex).
• Server=b.b.b.b,127.0.0.1 — proxy and localhost defined.
• SourceIP=c.c.c.c — matches expected value.
• TLS/Encryption fully disabled for testing:
TLSConnect=unencrypted, TLSAccept=unencrypted
• Everything on the agent side checks out — likely not the issue.
Proxy
Listening ports:
tcp LISTEN 0 4096 0.0.0.0:10051
tcp LISTEN 0 4096 [::]:10051
SELinux rules:
zabbix_agent_port_t tcp 10050
zabbix_port_t tcp 10051,10051
Connectivity:
nc -vz a.a.a.a 10051 → OK (to primary)
nc -vz c.c.c.c 10050 → OK (to agent)
Proxy details:
• ProxyMode=0 (Active)
• Server=a.a.a.a (Primary)
• Hostname= zabbixproxy.test.com
• Local DB configured:
DBHost=localhost, DBName=zabbix_proxy
• Timeout=30
• Unencrypted: TLSConnect=unencrypted, TLSAccept=unencrypted
• Verified startup log:
Starting Zabbix Proxy (active) [zabbixproxy.test.com]. Zabbix 7.4.1
Primary Server
Connectivity:
nc -vz b.b.b.b 10051 → OK (to proxy)
Listening ports:
tcp LISTEN 0 4096 0.0.0.0:10051
tcp LISTEN 0 4096 0.0.0.0:10050
tcp LISTEN 0 4096 [::]:10051
tcp LISTEN 0 4096 [::]:10050
Database → zabbix-db.test.com
• Connection + writes working fine.
• Timeout=4s (default 3s — likely fine).
• Server can ping and connect to both proxy and DB.Observed behavior:
- Server log confirms config is being sent:sending configuration data to proxy "zabbixproxy.test.com" at "b.b.b.b" datalen 15452, bytes 3999 (compression ratio 3.9)
- DB reflects correct host proxy linkage:hostid | host | status | proxyid | proxy_name -------+----------+--------+----------+----------------------------- 10775 | DEV-HTSM | 0 | 6 | zabbixproxy.test.com
- Proxy DB entry:
| proxyid | name | operating_mode | description | tls_connect | tls_accept | tls_issuer | tls_subject | tls_psk_identity | tls_psk | allowed_addresses | address | port | custom_timeouts | timeout_zabbix_agent | timeout_simple_check | timeout_snmp_agent | timeout_external_check | timeout_db_monitor | timeout_http_agent | timeout_ssh_agent | timeout_telnet_agent | timeout_script | local_address | local_port | proxy_groupid | timeout_browser |
| 6 | zabbixproxy.test.com | 0 | | 1 | 1 | | | | | b.b.b.b | b.b.b.b | 10051 | 0 | | | | | | | | | | | 10051 | NULL | |
- Proxy is online in UI.
- Agent configured to use proxy and has correct interface.
- Agent still appears offline.
tcpdump findings:
Primary server sends configuration; proxy receives data, but payload sizes differ slightly — possible truncation or early termination during config transfer.
Comment