From owner-freebsd-bugs@FreeBSD.ORG Mon Oct 8 02:20:09 2007 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6E53016A417 for ; Mon, 8 Oct 2007 02:20:09 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 4D85713C469 for ; Mon, 8 Oct 2007 02:20:09 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.1/8.14.1) with ESMTP id l982K9eZ054749 for ; Mon, 8 Oct 2007 02:20:09 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.1/8.14.1/Submit) id l982K9JL054747; Mon, 8 Oct 2007 02:20:09 GMT (envelope-from gnats) Date: Mon, 8 Oct 2007 02:20:09 GMT Message-Id: <200710080220.l982K9JL054747@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org From: "SBrickey.Net - Me" Cc: Subject: Re: kern/117000: [carp] CARP using address-less host NIC (carpdev) X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: "SBrickey.Net - Me" List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Oct 2007 02:20:09 -0000 The following reply was made to PR kern/117000; it has been noted by GNATS. From: "SBrickey.Net - Me" To: , "SBrickey.Net - Me" Cc: Subject: Re: kern/117000: [carp] CARP using address-less host NIC (carpdev) Date: Sun, 7 Oct 2007 22:04:43 -0400 This is a multi-part message in MIME format. ------_=_NextPart_001_01C8094F.97A79F3F Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Remko, =20 Apologies... CARP is a redundancy protocol in which (one or) multiple host computers participate in listening and responding from a virtual IP (similar to an alias, but the IP and its traffic is shared/split among the host computers)... allows for some REALLY redundant router configurations. =20 The issue is that when CARP first came out (from OpenBSD), the virtual IP was created based on the IP/subnets of the hosts' physical NICs... so the virtual IP had to be within the network/subnet of the host NIC... From what little analysis I performed, it seemed that traffic would be transmitted with a source address of the host NIC (it would "listen" on the CARP address, but respond from the host NIC)... this requires that an address space of Host+CARP addresses be available on the desired network... This means that for small addresses (say single static IP's as are common in the small business sector), CARP is not an option as the networks are too "small" (few IP's) for the ISP's gateway to acknowledge the hosts. =20 This is what was ported to FBSD... =20 In the meantime, the OpenBSD team has responded to this by adding a "carpdev" option to the interface which allows specifying the interface directly without referencing IP/subnet range... this allows the host NIC to remain IP-less, while supporting the virtual IP... allowing for CARP to function in limited environments such as single IP addresses. =20 This update would be WONDERFUL to have in the FBSD port. If further clarification is necessary please feel free to say so. =20 Thanks, -Scott ------_=_NextPart_001_01C8094F.97A79F3F Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Remko,

 

Apologies… CARP is a redundancy protocol in = which (one or) multiple host computers participate in listening and responding from = a virtual IP (similar to an alias, but the IP and its traffic is = shared/split among the host computers)… allows for some REALLY redundant router configurations.

 

The issue is that when CARP first came out (from = OpenBSD), the virtual IP was created based on the IP/subnets of the hosts’ = physical NICs… so the virtual IP had to be within the network/subnet of the = host NIC… From what little analysis I performed, it seemed that traffic = would be transmitted with a source address of the host NIC (it would = “listen” on the CARP address, but respond from the host NIC)… this requires = that an address space of Host+CARP addresses be available on the desired = network…

This means that for small addresses (say single = static IP’s as are common in the small business sector), CARP is not an option as = the networks are too “small” (few IP’s) for the = ISP’s gateway to acknowledge the hosts.

 

This is what was ported to = FBSD…

 

In the meantime, the OpenBSD team has responded to =  this by adding a “carpdev” option to the interface which allows specifying the interface directly without referencing IP/subnet = range… this allows the host NIC to remain IP-less, while supporting the virtual = IP… allowing for CARP to function in limited environments such as single IP addresses.

 

This update would be WONDERFUL to have in the FBSD = port.

If further clarification is necessary please feel = free to say so.

 

Thanks,

-Scott

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