Network Services And Operations
101 incident problems about Network Services And Operations. Start with the reviewed ones.
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When DNS changed but some clients still hit the old backendAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when the DNS record is updated but resolver cache, HTTP/2 keepalive, or client pools hold on to the old target.Network3 min readWhen firewalld looks open but connections keep getting blockedAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when a port rule appears to exist but the connection fails because of zone, runtime/permanent drift, source binding, or an upstream firewall.Network3 min readHow to separate timeout and connection refused by network pathAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when DNS, route, firewall, proxy, and listener states all look like the same connection failure.Network3 min read
Recommended problems
Reviewed problems first, then problems with detailed scenarios.
502 Bad Gateway: every page fails after a PHP upgrade502 Bad Gateway: every page fails (Network Services And Operations) is a hands-on troubleshooting drill. Read nginx's upstream error to see why it cannot reach php-fpm. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current...ReviewedNetworkBeginner3 minFree502 Bad Gateway: Nginx cannot connect to its upstream after an app upgrade502 Bad Gateway: Nginx cannot connect to its upstream is a hands-on troubleshooting drill. Read Nginx's upstream error to find why the proxy cannot reach the app. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live...ReviewedNetworkBeginner14 minFree504 Gateway Timeout: a slow export endpoint behind a 60-second proxy timeout504 Gateway Timeout: a slow export endpoint behind a 60-second proxy timeout is a hands-on troubleshooting drill. Match the proxy timeout with how long the upstream actually takes, and fix long requests properly. Network Services And Operations needs to be checked by narrowing...ReviewedNetworkIntermediate16 minFree504 Gateway Timeout: only the order list fails after a table migration504 Gateway Timeout: only the order list fails is a hands-on troubleshooting drill. A 504 means the upstream answered too slowly; find out why. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live signal before rollb...ReviewedNetworkBeginner3 minFreeConnection refused only from other servers: curl works on the hostConnection refused only from other servers: curl works on the host is a hands-on troubleshooting drill. Check which address a service listens on. Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live signal before rollback....ReviewedNetworkBeginner3 minFreeConnection refused vs connection timed out: what is the difference?Connection refused vs connection timed out: what is the difference? is a hands-on troubleshooting drill. Use the kind of connect error to decide where the connection stopped. Network Services And Operations needs to be checked by narrowing scope, recent change, and the current...ReviewedNetworkBeginner3 minFree
All problems (101)
Connection refused vs connection timed out: what is the difference?Connection refused vs connection timed out: what is the difference? is a hands-on troubleshooting drill. Use the kind of connect error to decide where the connection stopped. Network Services And Operations needs to be checked by narrowing scope, recent change, and the current...ReviewedNetworkBeginner3 minFree502 Bad Gateway: every page fails after a PHP upgrade502 Bad Gateway: every page fails (Network Services And Operations) is a hands-on troubleshooting drill. Read nginx's upstream error to see why it cannot reach php-fpm. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current...ReviewedNetworkBeginner3 minFree504 Gateway Timeout: only the order list fails after a table migration504 Gateway Timeout: only the order list fails is a hands-on troubleshooting drill. A 504 means the upstream answered too slowly; find out why. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live signal before rollb...ReviewedNetworkBeginner3 minFreeConnection refused only from other servers: curl works on the hostConnection refused only from other servers: curl works on the host is a hands-on troubleshooting drill. Check which address a service listens on. Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live signal before rollback....ReviewedNetworkBeginner3 minFree504 Gateway Timeout: a slow export endpoint behind a 60-second proxy timeout504 Gateway Timeout: a slow export endpoint behind a 60-second proxy timeout is a hands-on troubleshooting drill. Match the proxy timeout with how long the upstream actually takes, and fix long requests properly. Network Services And Operations needs to be checked by narrowing...ReviewedNetworkIntermediate16 minFree502 Bad Gateway: Nginx cannot connect to its upstream after an app upgrade502 Bad Gateway: Nginx cannot connect to its upstream is a hands-on troubleshooting drill. Read Nginx's upstream error to find why the proxy cannot reach the app. NGINX Network Services And Operations needs to be checked by narrowing scope, recent change, and the current live...ReviewedNetworkBeginner14 minFreeNETWORK-107DHCP relay uses the correct helper address but the source interface belongs to the wrong VRF so replies never returnDiscover messages leave the switch, yet offers vanish because the server replies into a routing context that has no path back to the client segment.NetworkIntermediate17 minFreeNETWORK-1792A DHCP relay exists and one subnet still missesOne subnet still misses DHCP after the relay update.NetworkBeginner6 minFreeNETWORK-1681A DHCP relay is configured and one subnet still failsA subnet still fails after the DHCP relay was updated.NetworkBeginner6 minFreeNETWORK-1691A DHCP relay is configured and one subnet still failsA subnet still fails after the DHCP relay was updated.NetworkBeginner6 minFreeNETWORK-1712A DHCP relay is configured and one subnet still failsA subnet still fails after the relay update.NetworkBeginner6 minFreeNETWORK-1722A DHCP relay is configured and one subnet still failsA subnet still fails after the relay update.NetworkBeginner6 minFreeNETWORK-1732A DHCP relay is configured and one subnet still failsA subnet still fails after the relay update.NetworkBeginner6 minFreeNETWORK-1742A DHCP relay is configured and one subnet still failsA subnet still fails after the relay update.NetworkBeginner6 minFreeNETWORK-1762A DHCP relay is configured and one subnet still failsA subnet still fails after the relay update.NetworkBeginner6 minFreeNETWORK-1782A DHCP relay is configured and one subnet still missesOne subnet still misses DHCP after the relay update.NetworkBeginner6 minFreeNETWORK-1621A DHCP relay is correct and one subnet still failsOne subnet still fails after a DHCP server move.NetworkBeginner6 minFreeNETWORK-1651A DHCP relay is correct and one subnet still failsOne subnet still fails after a DHCP server move.NetworkBeginner6 minFreeNETWORK-1661A DHCP relay is correct and one subnet still failsOne subnet still fails after a DHCP relay cleanup.NetworkBeginner6 minFreeNETWORK-1671A DHCP relay is correct and one subnet still failsA subnet still fails after the DHCP server address was updated on the relay.NetworkBeginner6 minFree