Latest Articles - Page 3

Map Microsoft Active Directory security groups to Keycloak realm roles with the LDAP group mapper, memberOf membership, nested group hierarchy, group sync, and access-token verification on Keycloak 26.7.3.

Integrate Keycloak 26.7.3 with Microsoft Active Directory—LDAP user federation, StartTLS, user sync, AD password login through Keycloak, and READ_ONLY vs WRITABLE edit modes.

Check whether an x86 CPU supports 2 MB or 1 GB HugePages, find the current HugeTLB default size, and change default_hugepagesz persistently with grubby on RHEL.

Create a general-purpose Amazon S3 bucket with modern ownership and access defaults, upload a file, use a presigned URL for temporary access, and verify objects with the AWS CLI.

Create an Amazon ElastiCache for Redis cluster in the AWS console, place it in a VPC subnet group, restrict port 6379 with a security group, and verify PING and SET from a Linux EC2 instance.

Increase or shrink tmpfs on Linux with size=, /etc/fstab, and mount -o remount. Covers /dev/shm, /run, and systemd /run/user limits on RHEL-family systems.

Create a gp3 EBS volume, attach and mount it on a Linux EC2 instance in the same Availability Zone, write data, keep the volume after termination, snapshot it, and restore the file from a new volume.

Free, hands-on Wireshark course covering packet capture, display filters, TCP analysis, TLS and IPsec decryption, and network troubleshooting.

Create an Amazon DynamoDB table with a partition key, add items in the console, read data with scan and get-item in the AWS CLI, and compare on-demand with provisioned capacity.

Create a Cognito user pool with Managed login and a public OAuth app client, sign in through the login page, link an identity pool, and verify STS temporary credentials from a user pool ID token.

Publish plain HTML, CSS, JavaScript, and images on AWS Amplify Hosting with HTTPS on an amplifyapp.com URL, using zip upload or GitHub, then connect a custom domain with managed TLS.

Host plain HTML, CSS, JavaScript, and images on Cloudflare Pages with free HTTPS and a pages.dev URL, then optionally attach your own domain when the zone uses Cloudflare DNS.

Publish plain HTML, CSS, JavaScript, and images on GitHub Pages with a free github.io URL and HTTPS, using the GitHub web interface—no web server to manage.

Spot QUIC and HTTP/3 in Wireshark, filter Initial and Handshake packets, load SSLKEYLOGFILE secrets to decrypt streams, and compare UDP QUIC with TCP HTTPS on the same service.

Find and filter 802.1Q VLAN IDs in Wireshark, compare trunk and access captures, and explain when the VLAN header is missing because the tag was stripped before the frame reached your NIC.

Install dnsmasq on RHEL 10, cache DNS on loopback, point upstream resolvers at a dedicated file, persist 127.0.0.1 through NetworkManager, and verify cache behavior with dig and tcpdump.

Authorize Samba shares for Active Directory users and groups on a RHEL 10 Winbind member server: valid users, Unix permissions, POSIX ACLs, SELinux, firewall, and Windows access tests.

Authenticate vsftpd FTP logins with Active Directory on RHEL 10 through PAM and SSSD, with deprecation notes, SELinux, passive ports, and tests—prefer SFTP for new deployments.

Let Active Directory users transfer files over SFTP on RHEL 10 after a realmd and SSSD join: sshd, PAM, home directories, optional chroot, and verification from Linux clients.

Join RHEL 10 to Active Directory with Samba Winbind using realm join or net ads join, verify wbinfo and getent, and publish an AD-authenticated Samba share.

Join RHEL 10 or Rocky Linux 10 to Windows Server 2025 Active Directory with realmd, adcli, and SSSD. Discover the domain, run realm join, verify Kerberos, and control AD logins.

Enroll RHEL 10 in Active Directory with adcli join, then configure SSSD, authselect, and NSS yourself—without realm join—for full control of the AD computer account.

Plan monthly AWS costs first, then host a static site on Amazon S3 behind CloudFront with a public ACM certificate, Route 53 DNS, and HTTPS on your own domain—without exposing the bucket to the public internet.

Read Wireshark when DNS fails: NXDOMAIN vs NODATA, SERVFAIL, REFUSED, missing responses, retransmitted queries, and slow answers using dns.time and dns.response_missing.

Read Wireshark captures when TCP will not connect: healthy SYN/SYN-ACK/ACK, immediate RST/ACK, repeated SYN retransmissions, and SYN-ACK retransmissions when the final ACK is missing.

Wireshark flags TCP Previous segment not captured when sequence numbers jump in your trace; learn how to tell late capture, real packet loss, and capture drops from ACK and retransmission evidence.

Join FreeRADIUS to Active Directory with Samba Winbind, authenticate MSCHAPv2 through ntlm_auth, and return a different reply for each AD group.

Paste Wireshark display filters for an IPv4 or IPv6 host, a two-host conversation, a CIDR subnet, and an exclusion, plus short checks for fragments, the Don't Fragment bit, and TTL.

Capture packets on a remote Linux host from local Wireshark over SSH with SSHDump, without installing Wireshark on the server.

Match IPv4 fragments in Wireshark by Identification and offset, confirm reassembly, and separate a DF path-MTU failure from a large offload capture.