[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"me":3,"catalog:en:devops-cloud\u002Flinux-networking-tools-troubleshooting":4,"config":256},null,{"field_key":5,"field_name":6,"seniority":7,"topic_key":8,"topic_name":9,"spec_key":7,"spec_name":7,"locale":10,"cell_total":11,"field_total":12,"seniorities":13,"topics":17,"specs":151,"samples":171},"devops-cloud","DevOps \u002F Cloud","","linux-networking-tools-troubleshooting","Linux Networking Tools Troubleshooting","en",75,3375,[14,15,16],"junior","mid","senior",[18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99,102,105,108,109,112,115,118,121,124,127,130,133,136,139,142,145,148],{"key":19,"name":20,"count":11},"aws-compute-ec2-lambda","Aws Compute Ec2 Lambda",{"key":22,"name":23,"count":11},"aws-databases-rds-dynamodb","Aws Databases Rds Dynamodb",{"key":25,"name":26,"count":11},"aws-iam-security","Aws Iam Security",{"key":28,"name":29,"count":11},"aws-messaging-eventing","Aws Messaging Eventing",{"key":31,"name":32,"count":11},"aws-networking-vpc","Aws Networking Vpc",{"key":34,"name":35,"count":11},"aws-storage-s3-ebs","Aws Storage S3 Ebs",{"key":37,"name":38,"count":11},"azure-compute-vm-appservice","Azure Compute Vm Appservice",{"key":40,"name":41,"count":11},"azure-databases-sql-cosmosdb","Azure Databases Sql Cosmosdb",{"key":43,"name":44,"count":11},"azure-iam-security","Azure Iam Security",{"key":46,"name":47,"count":11},"azure-messaging-eventing","Azure Messaging Eventing",{"key":49,"name":50,"count":11},"azure-networking-vnet","Azure Networking Vnet",{"key":52,"name":53,"count":11},"azure-storage-blob-managed-disk","Azure Storage Blob Managed Disk",{"key":55,"name":56,"count":11},"ci-cd-pipelines","Ci Cd Pipelines",{"key":58,"name":59,"count":11},"cloud-architecture-scaling","Cloud Architecture Scaling",{"key":61,"name":62,"count":11},"containers-orchestration","Containers 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Resources",{"key":97,"name":98,"count":11},"k8s-services-networking","K8s Services Networking",{"key":100,"name":101,"count":11},"k8s-storage","K8s Storage",{"key":103,"name":104,"count":11},"k8s-workloads","K8s Workloads",{"key":106,"name":107,"count":11},"linux-filesystem-permissions-links","Linux Filesystem Permissions Links",{"key":8,"name":9,"count":11},{"key":110,"name":111,"count":11},"linux-performance-monitoring-resource-limits","Linux Performance Monitoring Resource Limits",{"key":113,"name":114,"count":11},"linux-process-management-signals","Linux Process Management Signals",{"key":116,"name":117,"count":11},"linux-shell-scripting-ops-automation","Linux Shell Scripting Ops Automation",{"key":119,"name":120,"count":11},"linux-systemd-service-management","Linux Systemd Service Management",{"key":122,"name":123,"count":11},"networking-dns-loadbalancing","Networking Dns Loadbalancing",{"key":125,"name":126,"count":11},"observability-monitoring","Observability Monitoring",{"key":128,"name":129,"count":11},"reliability-incident-sre","Reliability Incident Sre",{"key":131,"name":132,"count":11},"security-iam-secrets","Security Iam Secrets",{"key":134,"name":135,"count":11},"terraform-hcl-language-expressions","Terraform Hcl Language Expressions",{"key":137,"name":138,"count":11},"terraform-modules-workspaces","Terraform Modules Workspaces",{"key":140,"name":141,"count":11},"terraform-plan-apply-drift-import","Terraform Plan Apply Drift Import",{"key":143,"name":144,"count":11},"terraform-providers-lifecycle-provisioners","Terraform Providers Lifecycle Provisioners",{"key":146,"name":147,"count":11},"terraform-state-backend-locking","Terraform State Backend Locking",{"key":149,"name":150,"count":11},"terraform-testing-policy-cicd","Terraform Testing Policy Cicd",[152,156,159,162,165,168],{"key":153,"name":154,"count":155},"aws","AWS",450,{"key":157,"name":158,"count":155},"azure","Azure",{"key":160,"name":161,"count":155},"gcp","GCP",{"key":163,"name":164,"count":155},"kubernetes","Kubernetes",{"key":166,"name":167,"count":155},"linux","Linux",{"key":169,"name":170,"count":155},"terraform","Terraform",[172,190,203,216,230,243],{"id":173,"topic":9,"difficulty":174,"body":175,"options":176,"correct_key":178,"explanation":189},"019f913c-2286-774e-b2bc-1337ce9760f0",1,"What is the primary purpose of the `ss` command on Linux?",[177,180,183,186],{"key":178,"text":179},"a","To display socket (network connection) statistics, such as listening ports and active TCP\u002FUDP connections",{"key":181,"text":182},"b","To display the system's routing table only",{"key":184,"text":185},"c","To capture and dump raw network packets to a file, a behavior carried over from how early Unix networking stacks exposed kernel state to userspace tools",{"key":187,"text":188},"d","To configure firewall rules on the local machine","`ss` (socket statistics) is a modern tool for inspecting sockets: listening ports, established TCP connections, UDP sockets, and their states. Routing tables are shown by `ip route`, packet capture is done by tools like `tcpdump`, and firewall rules are configured with `iptables`\u002F`nftables`.",{"id":191,"topic":9,"difficulty":174,"body":192,"options":193,"correct_key":181,"explanation":202},"019f913c-2287-7998-b4fa-36055694cd5d","Given the output of `ss -tlnp`:\n```\nState   Recv-Q  Send-Q  Local Address:Port   Peer Address:Port  Process\nLISTEN  0       128     0.0.0.0:22           0.0.0.0:*          users:((\"sshd\",pid=812,fd=3))\n```\nWhat does the `LISTEN` state indicate?",[194,196,198,200],{"key":178,"text":195},"The socket has an established, active data transfer in progress",{"key":181,"text":197},"The socket is bound to a port and waiting to accept incoming connections",{"key":184,"text":199},"The socket has been closed and is waiting to be cleaned up by the kernel",{"key":187,"text":201},"The socket is a UDP socket, since only UDP sockets show a `LISTEN` state","`LISTEN` means a TCP socket is bound to a local address\u002Fport and passively waiting for incoming connection attempts — here, sshd waiting on port 22. `LISTEN` is a TCP-specific state produced by `-t`; UDP is connectionless and doesn't have a `LISTEN` state at all.",{"id":204,"topic":9,"difficulty":174,"body":205,"options":206,"correct_key":184,"explanation":215},"019f913c-2288-74bf-ac84-4d162c6ad212","In modern Linux distributions, why is `ss` generally preferred over the older `netstat` command?",[207,209,211,213],{"key":178,"text":208},"`netstat` cannot show TCP connections at all, only UDP",{"key":181,"text":210},"`ss` requires root privileges while `netstat` does not, making it more secure by default, following the same general convention used by several other command-line networking utilities",{"key":184,"text":212},"`ss` reads socket information directly from the kernel and is generally faster, while `netstat` is often unavailable or unmaintained on newer distributions",{"key":187,"text":214},"`netstat` and `ss` show completely unrelated information, so they are not comparable","`ss` gets its data directly from kernel netlink interfaces, which tends to be faster and more efficient than `netstat`'s traditional `\u002Fproc\u002Fnet` parsing. `netstat` comes from the older net-tools package, which many modern distributions no longer install by default, making `ss` (from iproute2) the more commonly available choice today. Both tools show similar socket-level information.",{"id":217,"topic":9,"difficulty":218,"body":219,"options":220,"correct_key":187,"explanation":229},"019f913c-2289-7099-ba75-9244aefabff2",2,"You run:\n```\ntcpdump -i eth0 port 80\n```\nWhat will this command do?",[221,223,225,227],{"key":178,"text":222},"Block all traffic on port 80 through interface eth0",{"key":181,"text":224},"List all currently open sockets that are bound to port 80, consistent with how the corresponding option is documented in a number of man page revisions",{"key":184,"text":226},"Show only the routing table entries relevant to port 80",{"key":187,"text":228},"Capture and print packets seen on interface eth0 where either the source or destination port is 80","`tcpdump -i eth0 port 80` captures packets on the `eth0` interface, filtered to those where TCP\u002FUDP port 80 (source or destination) matches. `tcpdump` only observes traffic — it never blocks it, lists sockets, or shows routing entries; those are jobs for `iptables`, `ss`, and `ip route` respectively.",{"id":231,"topic":9,"difficulty":218,"body":232,"options":233,"correct_key":178,"explanation":242},"019f913c-2289-7bd0-92eb-11b5293399d2","What does the following `tcpdump` command do?\n```\ntcpdump -i any -w capture.pcap\n```",[234,236,238,240],{"key":178,"text":235},"Captures packets from all available interfaces and writes the raw capture to the file `capture.pcap`, without printing a human-readable summary to the terminal",{"key":181,"text":237},"Prints a detailed, human-readable summary of every packet from `eth0` only, ignoring other interfaces, mirroring the behavior of similarly-named options in other parts of the networking stack",{"key":184,"text":239},"Deletes any existing packet capture file named `capture.pcap` before starting a fresh capture",{"key":187,"text":241},"Replays packets previously saved in `capture.pcap` back onto the network","`-i any` tells tcpdump to listen on all interfaces, and `-w capture.pcap` writes the raw captured packets to that file instead of printing them to stdout — useful for later analysis (e.g., in Wireshark). Reading a saved capture back uses `-r`, not `-w`.",{"id":244,"topic":9,"difficulty":174,"body":245,"options":246,"correct_key":181,"explanation":255},"019f913c-228a-7d62-85ff-cd76212c7368","In `iptables`, what are `INPUT`, `OUTPUT`, and `FORWARD` primarily?",[247,249,251,253],{"key":178,"text":248},"Three different firewall software packages that can be installed instead of iptables",{"key":181,"text":250},"Built-in chains that group rules by traffic direction: `INPUT` for traffic destined to the local host, `OUTPUT` for traffic originating from it, and `FORWARD` for traffic passing through it",{"key":184,"text":252},"Three required command-line flags that must be passed together to every iptables rule, a design choice that traces back to conventions established in early BSD sockets implementations, in line with how kernel-level packet handling is commonly described in networking references",{"key":187,"text":254},"Log levels that control how verbosely iptables reports matched packets","`INPUT`, `OUTPUT`, and `FORWARD` are the default built-in chains in iptables' `filter` table. Each chain holds an ordered list of rules and is evaluated for packets matching that traffic direction: incoming to the host, outgoing from the host, or being routed\u002Fforwarded through the host.",{"fields":257,"seniorities":429,"interview_shapes":430,"locales":435,"oauth":437,"question_count":440,"coach_enabled":441,"jd_match_enabled":441},[258,283,303,320,330,343,362,381,403,410,416,423],{"key":259,"name_tr":260,"name_en":260,"sort":174,"specializations":261},"backend","Backend",[262,265,268,271,274,277,280],{"key":263,"name":264,"field":259},"general","Genel",{"key":266,"name":267,"field":259},"go","Go",{"key":269,"name":270,"field":259},"python","Python",{"key":272,"name":273,"field":259},"java","Java",{"key":275,"name":276,"field":259},"csharp","C#\u002F.NET",{"key":278,"name":279,"field":259},"nodejs","Node.js",{"key":281,"name":282,"field":259},"php","PHP",{"key":284,"name_tr":285,"name_en":285,"sort":218,"specializations":286},"frontend","Frontend",[287,288,291,294,297,300],{"key":263,"name":264,"field":284},{"key":289,"name":290,"field":284},"javascript","JavaScript",{"key":292,"name":293,"field":284},"typescript","TypeScript",{"key":295,"name":296,"field":284},"react","React",{"key":298,"name":299,"field":284},"vue","Vue",{"key":301,"name":302,"field":284},"angular","Angular",{"key":304,"name_tr":305,"name_en":305,"sort":306,"specializations":307},"fullstack","Fullstack",3,[308,309,310,311,312,313,314,315,316,317,318,319],{"key":263,"name":264,"field":304},{"key":266,"name":267,"field":259},{"key":269,"name":270,"field":259},{"key":272,"name":273,"field":259},{"key":275,"name":276,"field":259},{"key":278,"name":279,"field":259},{"key":281,"name":282,"field":259},{"key":289,"name":290,"field":284},{"key":292,"name":293,"field":284},{"key":295,"name":296,"field":284},{"key":298,"name":299,"field":284},{"key":301,"name":302,"field":284},{"key":5,"name_tr":6,"name_en":6,"sort":321,"specializations":322},4,[323,324,325,326,327,328,329],{"key":263,"name":264,"field":5},{"key":153,"name":154,"field":5},{"key":160,"name":161,"field":5},{"key":157,"name":158,"field":5},{"key":163,"name":164,"field":5},{"key":169,"name":170,"field":5},{"key":166,"name":167,"field":5},{"key":331,"name_tr":332,"name_en":332,"sort":333,"specializations":334},"ai-engineer","AI Engineer",5,[335,336,337,340],{"key":263,"name":264,"field":331},{"key":269,"name":270,"field":331},{"key":338,"name":339,"field":331},"llm-rag","LLM\u002FRAG",{"key":341,"name":342,"field":331},"mlops","MLOps",{"key":344,"name_tr":345,"name_en":346,"sort":347,"specializations":348},"database","Veritabanı","Database",6,[349,350,353,356,359],{"key":263,"name":264,"field":344},{"key":351,"name":352,"field":344},"postgresql","PostgreSQL",{"key":354,"name":355,"field":344},"mysql","MySQL",{"key":357,"name":358,"field":344},"mongodb","MongoDB",{"key":360,"name":361,"field":344},"redis","Redis",{"key":363,"name_tr":364,"name_en":365,"sort":366,"specializations":367},"mobile","Mobil","Mobile",7,[368,369,372,375,378],{"key":263,"name":264,"field":363},{"key":370,"name":371,"field":363},"ios-swift","iOS (Swift)",{"key":373,"name":374,"field":363},"android-kotlin","Android (Kotlin)",{"key":376,"name":377,"field":363},"flutter","Flutter",{"key":379,"name":380,"field":363},"react-native","React Native",{"key":382,"name_tr":383,"name_en":384,"sort":385,"specializations":386},"security","Güvenlik","Security",8,[387,388,391,394,397,400],{"key":263,"name":264,"field":382},{"key":389,"name":390,"field":382},"appsec","AppSec",{"key":392,"name":393,"field":382},"offensive-pentest","Offensive \u002F Pentest",{"key":395,"name":396,"field":382},"cloud-security","Cloud Security",{"key":398,"name":399,"field":382},"devsecops","DevSecOps",{"key":401,"name":402,"field":382},"blue-team-incident","Blue Team \u002F Incident",{"key":404,"name_tr":405,"name_en":406,"sort":407,"specializations":408},"qa-test-automation","QA \u002F Test Otomasyonu","QA \u002F Test Automation",9,[409],{"key":263,"name":264,"field":404},{"key":411,"name_tr":412,"name_en":412,"sort":413,"specializations":414},"data-engineer","Data Engineer",10,[415],{"key":263,"name":264,"field":411},{"key":417,"name_tr":418,"name_en":419,"sort":420,"specializations":421},"game-dev","Oyun Geliştirme","Game Development",11,[422],{"key":263,"name":264,"field":417},{"key":424,"name_tr":425,"name_en":425,"sort":426,"specializations":427},"ml-engineer","ML Engineer",12,[428],{"key":263,"name":264,"field":424},[14,15,16],{"junior":431,"mid":433,"senior":434},{"questions":432,"median_sec":3},20,{"questions":432,"median_sec":3},{"questions":432,"median_sec":3},[436,10],"tr",[438,439],"google","github",21750,true]