The ARP cache is currently set to the Linux kernel defaults: net.ipv4.neigh.default.gc_thresh1 = 128 net.ipv4.neigh.default.gc_thresh2 = 512 net.ipv4.neigh.default.gc_thresh3 = 1024 https://docs.kernel.org/networking/ip-sysctl.html In a test environment related to the UCS@school computer room module, the maximum number of 1024 cache entries was not enough and let to very long request times and request timeouts. It is conceivable that this can happen in customer environments with many connected devices and the "right" network setup during time windows where the most devices are active. Additionally, any containerized application may increase the number of entries in the ARP cache significantly, as all namespaced networks share the system level ARP cache. Proposal: Make these kernel values UCR configurable and set the default values to: net.ipv4.neigh.default.gc_thresh1 = 1024 net.ipv4.neigh.default.gc_thresh2 = 2048 net.ipv4.neigh.default.gc_thresh3 = 4096
Merged with commit 6d7187b6028e9fad3aa7e347d72bcf68fb9c5d1b ``` Successful build Package: univention-base-files Version: 9.0.9-2 Branch: 5.0-0 Scope: errata5.0-9 ```
Ported to 5.1 and 5.2: ``` Package: univention-base-files Version: 11.0.7 Branch: 5.2-0 ``` ``` Package: univention-base-files Version: 10.0.8 Branch: 5.1-0 ```
Change -> OK Install and upgrade -> OK YAML -> OK jenkins -> OK
<https://errata.software-univention.de/#/?erratum=5.0x1178>