[Debian 12 update!] sysctl config for linux server with 32 GB DDR RAM or more, SSD and 1Gbe (or faster) NIC

sysctl.conf

# IPv6 Configuration
# -> note that I have disabled ip6 for our internet-connection (wan/eth0) because
# -> my upstream/ISP (still) does not do IPv6. The rest, even localhost, does ip6 stuff.
net.ipv6.conf.all.disable_ipv6 = 0
net.ipv6.conf.default.disable_ipv6 = 0
net.ipv6.conf.lo.disable_ipv6 = 0
net.ipv6.conf.eth0.disable_ipv6 = 1
net.ipv6.conf.wan.disable_ipv6 = 1

# Packet Forwarding
net.ipv4.ip_forward = 1

# Security Settings
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0

# Connection Tracking
net.netfilter.nf_conntrack_max = 1048576
net.netfilter.nf_conntrack_buckets = 262144
net.netfilter.nf_conntrack_tcp_timeout_established = 86400
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 30

# Socket Buffer Sizes
net.core.rmem_max = 67108864
net.core.wmem_max = 67108864
net.ipv4.tcp_rmem = 4096 87380 67108864
net.ipv4.tcp_wmem = 4096 65536 67108864
net.core.rmem_default = 524288
net.core.wmem_default = 524288

# Backlog and Queuing
net.core.netdev_max_backlog = 60000
net.core.netdev_budget = 120000
net.core.netdev_budget_usecs = 48000
net.core.optmem_max = 8388608
net.core.default_qdisc = fq_codel

# TCP Settings
net.ipv4.tcp_congestion_control = bbr
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_sack = 1
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_fin_timeout = 5
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_mtu_probing = 1
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_retries2 = 5
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_sack = 1
net.ipv4.tcp_low_latency = 1
net.ipv4.tcp_adv_win_scale = 1

# Memory Settings
vm.min_free_kbytes = 524288
vm.swappiness = 0
vm.dirty_background_ratio = 5
vm.dirty_ratio = 10
vm.dirty_expire_centisecs = 3000
vm.dirty_writeback_centisecs = 500

# File Descriptors
fs.file-max = 2097152
fs.nr_open = 2097152

# Inotify Watches
fs.inotify.max_user_watches = 1048576

# Shared Memory Limits
kernel.shmmax = 17179869184
kernel.shmall = 4194304

# Kernel Miscellaneous
kernel.core_uses_pid = 1
kernel.domainname = your.local.server.domain.name
kernel.printk = 3 4 1 3
kernel.randomize_va_space = 2
kernel.sysrq = 0

# Load kernel parameters from /etc/sysctl.conf
sysctl -p 2>&1 > /dev/null

# Load system configuration
sysctl --system 2>&1 > /dev/null