Access to affected cloud services was restored by addressing issues at the customer router or LAN. In incidents caused by router-level adblocking or content filtering, disabling the router adblocker or whitelisting service endpoints (examples for Flex Insights: apigw.ytica.com and analytics.ytica.com) returned dashboard and analytics access. Where the router had become unresponsive or DHCP leases failed, power-cycling or restarting the router restored normal DHCP behavior and allowed Power BI, SharePoint, Teams, and other web services to load when workstation restarts had not helped. Support-level cache clearing (browser cache and Teams cache) was attempted in at least one case but did not resolve access until the underlying network issue was fixed. Mobile hotspots were used as temporary access workarounds; in some cases services continued to work after reconnecting to the original network. Tickets that were not resolved at initial support were escalated to Network Operations for further investigation; some records did not document a definitive root cause.

Investigations attributed most incidents to upstream/provider failures, regional ISP routing problems, and ISP‑level address translation or limited IPv4 paths (DS‑Lite/CGNAT) that broke IPv4 connectivity to third‑party services. Affected services repeatedly exhibited packet loss and latency (for example Microsoft Teams reported “poor network quality”; Twilio showed the orange‑triangle EKG “unstable connection”) even when local throughput/speed tests were normal. Connectivity was restored when the ISP/provider repaired the outage (NetCologne’s remediation restored full service for a Cologne campus) or when traffic was routed over an alternate IPv4‑capable path such as a mobile hotspot; local router reboots or network reinitialisation sometimes gave only temporary relief. Correlating affected users by location and upstream provider and checking provider status/outage reports confirmed provider‑side root causes in documented cases. Separately, at least one incident that appeared as a network restriction was an authentication/service‑side block: a ChatGPT sign‑in failure produced the error “In this network, sign‑in with this account is not possible” across multiple networks and accounts; no local network remediation was recorded and the case required escalation to the service/account team. Another case (IU Knowledge Center) was a transient external site outage that later resolved without documented remediation.

Most affected Lenovo Windows 10 laptops were restored after device-level remediation using the vendor system update utility (Lenovo System Update). Technicians installed and ran the Lenovo utility with administrator privileges, applied vendor-recommended system, driver, and firmware updates, and allowed devices to complete provisioning while powered and network-connected. Where the vendor update utility was absent or its installer failed due to limited rights, technicians remotely connected with elevated privileges to install and run updates. Missing or incorrectly provisioned client applications were reinstalled or re-provisioned as needed. These actions — particularly the vendor system update and associated driver/firmware updates — resolved previously failing web pages and intermittent Internet disconnections on the majority of endpoints. However, some devices continued to exhibit connectivity issues after Lenovo System Update completed, and those cases required additional device-level investigation and escalation.

Physical and network configuration fixes restored availability. Desk and workstation cabling was tidied and recabled (including four 2‑desk islands in Bochum) and cable protection/ties were specified where unsafe or exposed cabling was found; a Duisburg site was flagged in a fire‑safety audit for daisy‑chained power strips and exposed cables, and remediation steps (removal of daisy‑chaining, re‑provisioned power feeds and cable protection) were recorded as planned but not completed in that ticket. Network ports were activated on the correct switches and assigned to the appropriate VLAN (VLAN500) where required. DHCP reservations were updated with device MAC addresses so affected devices obtained their reserved IPs. Access points were repositioned and commissioned as part of remediation (eight APs repositioned in Bochum — two in room 07.04 including an opposite‑facing AP, two in room 07.11 — and all required APs were physically installed and commissioned for the new 2nd‑floor office in Leinfelden‑Echterdingen). Printer and workstation moves associated with office relocation were completed (printers moved and workstations reorganized 1:1). After these cabling, power‑infrastructure and network configuration changes, affected devices became reachable and services such as printing, auto‑install, scanning and access to infrastructure services (vCenter) were restored.

Cases were resolved by a combination of carrier-side provisioning fixes, SIM/eSIM reinstallation, and quota or tariff adjustments. Support checks of carrier provisioning (BSP) identified eSIMs that had never been activated; in several incidents removing obsolete physical SIMs and scanning the provided eSIM QR to reinstall/activate the eSIM restored voice and mobile-data service. Corporate data allowances were increased either via support-side tariff changes (examples: 3 GB→20 GB, other increases to ≥10 GB) or by users self-provisioning add‑ons through the MeinMagenta app or pass.telekom.de; short-term hotspot/top-up bundles were used when appropriate (one case used a 24‑hour unlimited add‑on at €5.95). Support observed that pass.telekom.de sometimes only detected the mobile tariff when opened over the device’s mobile connection; booking additional volume succeeded when the portal was accessed via the phone’s LTE connection or by using the MeinMagenta app. Roaming problems were attributed to tariff allowances or device roaming settings; support verified roaming inclusions with the carrier and requested screenshots when device messages persisted. For sites lacking fixed Internet, mobile-router “Würfel” devices were deployed as interim Internet (practically supporting only a handful of concurrent users, ~5 per device, with variable performance depending on reception). Organizational controls (cost-center/manager approval) sometimes delayed larger or roaming data purchases. Where quota readings were inconsistent or allowances were already large, support confirmed existing provisioned volume to avoid adding duplicate bundles.

All affected systems were standardized to use the central NTP server time.cpg.int. iDracs, ESXi hosts, vCenter, printers, Kentix, UPS units, switches, WLAN controllers and access points were updated to reference time.cpg.int, which aligned time across the infrastructure.

Support confirmed the CPG‑Corp SSID used the user's Windows/domain password and resolved access by assigning the user to the required WLAN access group. Connectivity became functional after directory/group membership propagation (approximately 1–2 hours).

Technicians investigated and restored office and corporate internet connectivity for impacted sites; affected users were contacted to confirm reconnection before incidents were closed. Localized WLAN failures in a campus library were resolved by deploying a new WLAN (new AP/SSID) and monitoring for follow‑up reports. Server‑room infrastructure work at Bad Honnef was performed by the infrastructure team; the intervention caused brief, expected disconnections during the maintenance window and resolved the underlying server‑room/network fault, after which users reported improved connectivity. Intermittent performance problems and telephony failures at the Studienberatung (StuBe MUC) were escalated to IT Infrastructure; scope and room details were collected and active measurements (a measurement workstation and line/bandwidth tests) were initiated to characterize suspected bandwidth saturation for further remediation. For planned electric meter replacement, affected circuits were powered down in advance where appropriate, the maintenance window was annotated in monitoring, and it was confirmed that network devices and servers would power back on and restore services when mains power returned.

Incidents manifested as gateway errors and severe slowness during peaks of client activity; resolution and observations varied by case. In a Miro classroom session, the root cause was identified as client-side internet capacity/bandwidth limits (exacerbated by browser behaviour and VPN use); when student join activity was staggered (sequential logins) and retries were attempted after the initial peak subsided, board performance improved and remaining students were able to connect. In a separate website applicant-portal incident, users saw an HTTP 502 Bad Gateway on contract submission but the contracts were transmitted and became visible after a delay; no technical fix was documented in that ticket and support indicated they did not have access to the applicant portal and advised engagement with the portal's support team. These records show that 500/502 symptoms can result from client-side capacity spikes and from transient gateway/backend delays where the backend may still complete work after the error is shown.

IT reviewed the inquiry and confirmed that Deutschlandticket ordering and related support were managed by HR rather than IT, and the user was directed to contact HR. IT did not modify the intranet or handle the ticket further.

The missing data file was retransmitted at 09:20 and the resend completed successfully; Carousel confirmed receipt and the delivery portal reflected the reservations. The initial connection failure was recorded but not diagnosed further in this record.

Support triaged these incidents as local/user-side network instability rather than platform outages. Support actions and observations included: - Advising use of a wired LAN where possible, improving Wi‑Fi signal strength (for example by moving closer to the router), and confirming whether the user was in an office or home office to identify location-specific instability. - For browser-based VoIP (Vonage), recommending clearing the browser cache and cookies; in at least one case the user had already cleared them and the issue persisted. - For Twilio-related incidents, requesting the Twilio Network Test, reviewing Twilio EKG results, and—for inconclusive tests—recording and collecting Twilio network logs following internal IUG procedures for further analysis. Tickets were closed after these diagnostic recommendations were provided; no Twilio/Vonage platform errors were identified in these cases.

The incident was diagnosed as a temporary network interruption. Network connectivity was restored and the myLIBF service returned to normal; service availability was confirmed after the network fault was cleared.

Investigations identified that network-layer interception and filtering were preventing the e-test client and admin tool from connecting to the server on TCP port 5656. Restoring connectivity required exempting the e-test server traffic from HTTPS-decryption/web-filter policies and allowing the server port through the perimeter filtering rules. After those policy changes the admin client and e-test users could establish connections and downloads completed successfully.

The network team reviewed each site and applied Meraki best-practice traffic-shaping settings. Sites that hosted only servers had QoS/shaping disabled to avoid inappropriate client-oriented policies. The changes were deployed and verified across all locations; the work was completed and confirmed as of 2024-11-06.

Legacy ACL entries were translated into Catalyst Center format and the ACLs were updated to replace the outdated management IPs. Specifically, the Intermapper address was changed from 7.22.77.177 to 10.30.103.6 and the JumpHost address from 7.22.64.9 to 10.30.105.4. The revised ACLs were pushed to the switches via Catalyst Center, which restored SSH and SNMP access from the management systems.