From 9e887b15a45ae4fd2569c6f48bd8540e3a4c0ff0 Mon Sep 17 00:00:00 2001 From: Hutson Date: Sun, 21 Dec 2025 11:16:42 -0500 Subject: [PATCH] Document MTU 9000 jumbo frames configuration MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Added MTU 9000 table showing all configured devices - Added verification commands for checking MTU - Added important note about bridge + physical interface MTU sync - Mac Mini, PVE, PVE2, TrueNAS, and router all support jumbo frames 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 --- CLAUDE.md | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/CLAUDE.md b/CLAUDE.md index 4da1666..24b2aa8 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -356,7 +356,32 @@ qm set VMID --net0 virtio,bridge=vmbr2 qm set VMID --net1 virtio,bridge=vmbr3 ``` -- MTU 9000 (jumbo frames) on all bridges +### MTU 9000 (Jumbo Frames) + +Jumbo frames are enabled across the network for improved throughput on large transfers. + +| Device | Interface | MTU | Persistent | +|--------|-----------|-----|------------| +| Mac Mini | en0 | 9000 | Yes (networksetup) | +| PVE | vmbr0, enp1s0 | 9000 | Yes (/etc/network/interfaces) | +| PVE2 | vmbr0, nic1 | 9000 | Yes (/etc/network/interfaces) | +| TrueNAS | enp6s18, enp6s19 | 9000 | Yes | +| UCG-Fiber | br0 | 9216 | Yes (default) | + +**Verify MTU:** +```bash +# Mac Mini +ifconfig en0 | grep mtu + +# PVE/PVE2 +ssh pve 'ip link show vmbr0 | grep mtu' +ssh pve2 'ip link show vmbr0 | grep mtu' + +# Test jumbo frames +ping -c 1 -D -s 8000 10.10.10.120 # 8000 + 8 byte header = 8008 bytes +``` + +**Important:** When setting MTU on Proxmox bridges, ensure BOTH the bridge (vmbr0) AND the underlying physical interface (enp1s0/nic1) have the same MTU, otherwise packets will be dropped. ### Tailscale VPN