Technical writing by Imran Sarwar. Start with Python network automation or the Netmiko, NETCONF and RESTCONF guide.
Implementation lessons, lab walkthroughs and design reviews for infrastructure teams. Each article links to related project evidence and a way to discuss a technical requirement.
For a working approach, read Python network automation with Netmiko and the multi-vendor configuration management project. If a connectivity symptom needs investigation first, use the NOC troubleshooting guide.
Need help adapting a workflow? Review Python network automation services, including script troubleshooting and Flask/API integration.
Browse network automation troubleshooting guides by topic.
Python network automation · Troubleshooting guide and proposed lab
Troubleshoot Netmiko ReadTimeout and pattern-not-detected errors with a proposed GNS3/EVE-NG lab, Python examples, prompt checks and session logs.
Read troubleshooting guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Handle Catalyst Center HTTP 429 with a bounded GET retry example, Retry-After parsing and request-budget guidance. Controller testing remains proposed.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Poll Cisco Catalyst Center API tasks with Python timeouts, validate isError and endTime, and keep task completion separate from device readback evidence.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Prepare Cisco PSIRT review reports from version inventory and saved advisory exports, preserving missing data and manual applicability decisions.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Review NAPALM compliance reports with a validator example and Python checks for missing, failed and skipped getters before showing a pass.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Investigate ncclient get_config timeouts with scoped filters, expected-node validation and separate RPC error states. Includes a proposed lab.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Inspect ncclient unknown-element errors with namespace-aware XML examples, a guarded config builder and clear boundaries for proposed device tests.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Check NETCONF startup, candidate and writable-running capabilities with ncclient and explicit URI matching before choosing a datastore workflow.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Build a Netmiko configuration capture workflow with atomic files, inventory validation and per-device failure reports. Includes a proposed GNS3/EVE-NG lab.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Complete a guarded Netmiko ping dialog with finite reads, unexpected-prompt checks and separate packet-loss reporting. Includes a proposed GNS3/EVE-NG lab.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Diagnose Netmiko TextFSM raw-string results with template lookup checks, an explicit parsing example and offline fixtures before testing your device image.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Retry only failed Nornir hosts with a complete offline inventory exercise, recovery assertions and guidance on safe retry eligibility and reporting.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Separate Paramiko host-key and KEX mismatches with version checks and an offline algorithm comparison before changing SSH policy.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Investigate Paramiko SSH banner errors with stage-specific timeouts, same-host SSH comparisons and a failure classifier for proposed lab testing.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Define pyATS pre/post-change acceptance checks with a testbed skeleton, a proposed Genie collector and offline comparisons of required interface state.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Compare network configuration drift with Python, approved baseline metadata and narrowly scoped normalization that preserves meaningful ACL changes.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Check TLS certificate expiry across approved inventory with Python, verified TLS, failure categories and last-success timestamps. Live probes remain untested.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Investigate IOS XE RESTCONF 401 errors with verified-TLS Python GET requests, response classification and checks for HTTP authentication and AAA.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Diagnose RESTCONF 404 on IOS XE by checking supported YANG models, resource paths and encoded interface keys, with Python path examples.
Read practical guide and proposed lab
Model-driven APIs · Practical guide and proposed lab
Understand RESTCONF 409 conflicts using error tags, repeat-create fixtures and readback decisions before choosing POST, PATCH or another change.
Read practical guide and proposed lab
CLI automation · Practical guide and proposed lab
Compare pinned Scrapli and Netmiko APIs, host-key policy, timeouts and result handling with equivalent IOS XE examples. No untested speed claims.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Review missing SD-Access access tunnels with AP, WLC and fabric-edge evidence. Includes synthetic identity checks and explicit platform prerequisites.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Trace an unreachable SD-Access endpoint through attachment, LISP, policy and return-path evidence. Python examples use synthetic records, not a live fabric.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Review SD-WAN Manager API 403 errors with a session-login helper, cookie/token checks and offline tests. Includes explicit release and access limits.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Investigate SD-WAN BFD failures using expected peer/color pairs, read-only CLI evidence and a Python matrix that preserves missing observations.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Review SD-WAN certificate failures with reason codes, trust, identity and clock evidence. Includes a synthetic Python case evaluator and proposed checks.
Read practical guide and proposed lab
Controller and fabric · Practical guide and proposed lab
Review SD-WAN template out-of-sync evidence using device identity, management model and task status before approving reconciliation or reattachment.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Separate Ubuntu routing and DNS failures using resolvectl, Netplan and a proposed GNS3/EVE-NG lab, with a small Python resolution test.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Trace Windows Update failures through system proxy, DNS, TLS and download policies before changing endpoints or bypassing security controls.
Read practical guide and proposed lab
Infrastructure diagnostics · Practical guide and proposed lab
Investigate Windows VPN error 720 with adapter-binding, address-allocation and event evidence before resetting network components.
Read practical guide and proposed lab
Cisco switching troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose a VLAN allowed on a Cisco trunk but not forwarding by checking local VLAN state, STP and pruning before a scoped missing-VLAN correction.
Read troubleshooting guide and hypothetical lab
Python network automation · Protocol comparison
Choose a Python network automation interface: compare Netmiko SSH, NETCONF RPCs, RESTCONF resources and vendor APIs, with capability and validation checks.
Read protocol comparison
Firewall and VPN troubleshooting · Troubleshooting guide and hypothetical lab
Trace FortiClient IKEv2 SAML failures through listener, IdP, group and tunnel stages before correcting a scoped pilot profile without weakening security.
Read troubleshooting guide and hypothetical lab
Cisco switching troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose Cisco native VLAN mismatches by mapping both trunk ends, untagged classification and STP protection before a controlled two-sided review.
Read troubleshooting guide and hypothetical lab
Windows VPN and directory diagnostics · Troubleshooting guide and hypothetical lab
Compare effective Windows VPN DNS policy, AD SRV answers and controller tunnel routes before a scoped split-DNS correction with explicit pilot rollback.
Read troubleshooting guide and hypothetical lab
Linux and virtualization · Troubleshooting guide and hypothetical lab
Compare host and container DNS paths, Docker network mode and service resolver overrides, then verify a scoped Compose DNS correction and rollback.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Troubleshoot RDP after TCP 3389 succeeds by checking listener identity, TLS, NLA and effective logon rights without disabling authentication controls.
Read troubleshooting guide and hypothetical lab
Network monitoring · Troubleshooting guide and hypothetical lab
Trace SNMP polling timeouts from the real collector through UDP 161, SNMPv3 security and source ACL checks, then verify a narrowly scoped correction.
Read troubleshooting guide and hypothetical lab
Python DNS and directory diagnostics · Troubleshooting guide and hypothetical lab
Check AD SRV records and target A/AAAA dependencies with Python, preserving DNS errors and partial answers through a narrow contract and offline fixtures.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Verify real DHCP scope exhaustion using lease states, exclusions and policy ranges before an approved same-subnet expansion with lease-aware rollback.
Read troubleshooting guide and hypothetical lab
Firewall troubleshooting · Troubleshooting guide and hypothetical lab
Troubleshoot Palo Alto DNAT traffic denied by security policy using original addresses, post-NAT destination zones, rule tests and real session evidence.
Read troubleshooting guide and hypothetical lab
Monitoring troubleshooting · Troubleshooting guide and hypothetical lab
Validate interface identity, counter continuity, actual poll interval and link speed before converting SNMP octets into utilization or congestion alerts.
Read troubleshooting guide and hypothetical lab
Routing troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose a Cisco BGP neighbor stuck Active by checking peering source, underlay routes and TCP 179 before changing BGP policy or authentication.
Read troubleshooting guide and hypothetical lab
Routing troubleshooting · Troubleshooting guide and hypothetical lab
Investigate BGP flaps during large exchanges using peer reset evidence, source-specific DF probes and TCP retransmissions before a scoped PMTUD repair.
Read troubleshooting guide and hypothetical lab
Linux networking · Troubleshooting guide and hypothetical lab
Troubleshoot Ubuntu static routes using Netplan ownership, renderer, policy rules and source-specific lookups, with a guarded route correction and rollback.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Troubleshoot Group Policy not applying with gpresult, OU links, security and WMI filters, processing events, and a scoped disabled-link correction.
Read troubleshooting guide and hypothetical lab
Security control selection · Architecture study notes
A practical network security architecture review: map requirements to identity, segmentation, certificates and telemetry, then define validation and ownership.
Read architecture study notes
Python network monitoring · Troubleshooting guide and hypothetical lab
Build a bounded Python Net-SNMP wrapper that keeps valid zero, missing OIDs, no response and collector errors separate, with reproducible offline fixtures.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Troubleshoot Windows domain time synchronization using source, effective policy, UDP 123 and service events before restoring a member's domain hierarchy.
Read troubleshooting guide and hypothetical lab
Routing troubleshooting · Troubleshooting guide and hypothetical lab
Trace one BGP prefix from local origination through export, import, best-path selection and RIB installation before a scoped prefix-list correction.
Read troubleshooting guide and hypothetical lab
Network troubleshooting · Operational experience notes
Is a connectivity complaint a network or endpoint issue? Follow a NOC workflow using scope, path checks, comparison tests and evidence-led escalation.
Read operational experience notes
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Trace DHCP clients that get no lease despite free scope addresses using VLAN, scope and DORA checkpoints, with a controlled relay-helper correction.
Read troubleshooting guide and hypothetical lab
Routing troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose OSPF EXSTART or EXCHANGE failures by comparing DBD MTU checks with path capacity, then verify a scoped IP MTU correction and rollback.
Read troubleshooting guide and hypothetical lab
NOC and observability · Operational troubleshooting guide
Understand network visibility versus observability with NOC examples: logs, metrics, flows, traces, service dependencies and a practical incident evidence record.
Read operational troubleshooting guide
Monitoring troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose missing SNMP values by separating numeric OID instances, platform support and read-view restrictions while preserving the same poller identity.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Troubleshoot AD domain controller discovery with resolver selection, SRV records, DC Locator and service-path checks before a client-only DNS correction.
Read troubleshooting guide and hypothetical lab
Secure infrastructure delivery · Deployment checklist
An infrastructure security-by-design checklist covering access paths, management boundaries, certificates, logging and recovery evidence before deployment.
Read deployment checklist
Python switching diagnostics · Troubleshooting guide and hypothetical lab
Compare expected LACP members with observed IOS XE output while keeping collection and parser errors separate, using a read-only contract and offline tests.
Read troubleshooting guide and hypothetical lab
Linux and virtualization · Troubleshooting guide and hypothetical lab
Diagnose an unreachable Docker published port by separating the app listener, container bind, host mapping and external policy before a scoped correction.
Read troubleshooting guide and hypothetical lab
Cisco switching troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose Cisco LACP EtherChannel suspended or individual ports using member flags, peer identity and negotiation checks before a scoped lab correction.
Read troubleshooting guide and hypothetical lab
Resilience and recovery · Infrastructure review guide
Review network security resilience through failure domains, management access, dependency checks and recovery evidence. A practical infrastructure test framework.
Read infrastructure review guide
Cisco switching operations · Troubleshooting guide and hypothetical lab
Capture switch migration VLAN, STP and LACP baselines, compare expected forwarding after cutover, and use explicit service acceptance and rollback gates.
Read troubleshooting guide and hypothetical lab
Windows Server infrastructure · Troubleshooting guide and hypothetical lab
Locate SMB access denied at authentication, share connection or file access, then verify a scoped read permission without broadening NTFS or share access.
Read troubleshooting guide and hypothetical lab
Routing troubleshooting · Troubleshooting guide and hypothetical lab
Diagnose HSRP dual-active by comparing group identity, VLAN continuity and two-way hello delivery before a scoped trunk repair and forwarding checks.
Read troubleshooting guide and hypothetical lab
Cisco switching troubleshooting · Troubleshooting guide and hypothetical lab
Troubleshoot a Cisco VLAN that cannot ping its gateway using access-port, trunk, STP and SVI checks, with a scoped correction and rollback example.
Read troubleshooting guide and hypothetical lab
Firewall and routing troubleshooting · Troubleshooting guide and hypothetical lab
Trace missing Palo Alto return traffic using exact flow tuples, session counters and endpoint routes before correcting a demonstrated firewall bypass.
Read troubleshooting guide and hypothetical lab
Applied machine learning · Lab evaluation guide
Build a credible ML intrusion-detection experiment with traffic features, leakage checks, precision/recall and analyst review. Lessons from a Python Flask lab.
Read lab evaluation guide
Network security design · Lab-informed design guide
Translate Zero Trust into network design decisions: resource inventory, identity checks, segmentation, least privilege and policy validation with lab examples.
Read lab-informed design guide
Identity and access management · Lab-informed technical guide
Review OpenStack Keystone IAM with RBAC, least privilege and access-review examples. Understand role scope, lifecycle checks and audit evidence.
Read lab-informed technical guide
Network change automation · Operational implementation notes
Review multi-vendor ACL automation across Cisco, Juniper, HP and Brocade: policy intent, device-specific behavior, prompt handling and post-change validation.
Read operational implementation notes
Flask and cloud IAM · Project architecture walkthrough
Inside IDMUI, a Python Flask interface for OpenStack Keystone. Explore scoped role assignments, API errors, session handling and infrastructure dashboard design.
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Applied AI and Python · Practical overview
Explore AI use cases for infrastructure teams, from traffic classification to text analysis. A practical guide to data quality, evaluation and human review.
Read practical overview
Python network automation · Implementation walkthrough
Plan multi-vendor user management with Python and Netmiko: inventory, SSH sessions, prompt handling, configuration checks and per-device results.
Read implementation walkthrough
Network infrastructure · Lab troubleshooting guide
A Cisco Packet Tracer lab on port security, routed LANs and wireless access, with MAC learning checks, violation modes and validation steps.
Read lab troubleshooting guide
Network infrastructure · Lab design walkthrough
A hybrid backup network lab explained: OSPF routing, GRE versus IPsec, traffic policy and failover checks. Design lessons from Imran Sarwar.
Read lab design walkthrough