From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate001.proxmox.com (gate001.proxmox.com [IPv6:2a0f:8001:1:32::40]) by lore.proxmox.com (Postfix) with ESMTPS id 52CBD1FF0AB for ; Wed, 21 Oct 2026 09:28:45 +0200 (CEST) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id E5067213C3; Wed, 21 Oct 2026 09:28:42 +0200 (CEST) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 21 Oct 2026 09:28:38 +0200 Message-Id: From: "Thomas Ellmenreich" To: "Stefan Hanreich" , Subject: Re: [PATCH pve-docs v2 1/1] network/sdn: update and clean up VLAN information X-Mailer: aerc 0.20.0 References: <20261020064508.32479-1-t.ellmenreich@proxmox.com> In-Reply-To: X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1792567718298 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.405 Adjusted score from AWL reputation of From: address DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment (newer systems) RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: DSH3WLN4GPPMSHFFG3DPVDCLMSVJDLCM X-Message-ID-Hash: DSH3WLN4GPPMSHFFG3DPVDCLMSVJDLCM X-MailFrom: t.ellmenreich@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox VE development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Tue Oct 20, 2026 at 3:54 PM CEST, Stefan Hanreich wrote: > On 10/20/26 8:45 AM, Thomas Ellmenreich wrote: [snip] >> +[[vlan_common_issues]] >> +Common Issues >> +^^^^^^^^^^^^^ >> + >> +.Issue: Configuring VLAN on interface that is member of bridge >> + >> +It's not recommended to configure a VLAN on an interface that is a memb= er of a >> +bridge. Doing so will "blackhole" all traffic of that VLAN on the bridg= e. > > Might need a more specific example so this becomes clearer? It's hard to = understand > otherwise imo. If I understand correctly, the example [0] you mention further down would b= e an instance of 'blackholing' the traffic. Perhaps I could mention that example here instead of creating a separate point for it. Is this assumption correct? >> + >> +.Issue: Limited number of tags when VLAN offloading to NIC >> + >> +Certain NIC's, only support VLAN offloading only for a reduced number o= f tags. >> +In these cases it is best to either reduce the VLAN tag range on the br= idge or >> +disable offloading altogether. The exact problems that can arise depend= on >> +the exact hardware used. > > There are two other pitfalls I can think of that can occur when configuri= ng > VLANs directly on top of physical interfaces: > > > When using a VLAN on the host (often the management VLAN) and starting a = guest > with a network device that has the same VLAN tag set, connectivity to the= host is > lost on that VLAN after starting the guest. > [0]: v > e.g.: > > # NIC that carries the VLANs > iface nic1 inet manual > =20 > # management VLAN > auto nic1.1337 > iface nic1.1337 inet static > address 10.133.7.10/24 > =20 > # non vlan-aware bridge > auto vmbr1 > iface vmbr1 inet manual > bridge-ports nic1 > bridge-stp off > bridge-fd 0 > > and then a guest: > > net0: name=3Deth0,bridge=3Dvmbr1,hwaddr=3DBC:24:11:86:69:F3,tag=3D1337,t= ype=3Dveth [snip]