Date: Sat, 27 Jan 1996 07:18:16 +0200 (SAT) From: John Hay <jhay@mikom.csir.co.za> To: terry@lambert.org (Terry Lambert) Cc: hackers@FreeBSD.ORG (FreeBSD-hackers) Subject: Re: NetBUI and/or IPX routing? Message-ID: <199601270518.HAA09078@zibbi.mikom.csir.co.za> In-Reply-To: <199601262014.NAA05110@phaeton.artisoft.com> from "Terry Lambert" at Jan 26, 96 01:14:45 pm
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> > > I think you are a bit sidetracked. The original question was if it is > > possible to have a Netware server on one side of a router and only IPX > > clients on the other side. (No Netware server on that side) > > > > ------------ ----------- ---------- > > | Netware | Net A | FreeBSD | Net B | IPX | > > | |-----------| |---------| | > > | Server | | Router | | Client | > > ------------ ----------- ---------- > > > > This is possible with Netware 3.11 and DOS and Windose clients. We are > > using it here. I don't have a Netware 4.xx server so I don't know if that > > will work. > > > > What happens is that the FBSD router will gather the IPX RIP and SAP > > information that is broadcast by the server (and others if there are more > > than one). When you start a IPX client it will do a SAP GetNearestServer > > request (broadcast) which the router will answer. This packet contains the > > name and address of the Netware Server. The client will then do a RIP > > request to find a router that will route packets to the server address that > > it just received. The router will answer it because it will see that it > > is the cheapest (only) route to the server. Only then the client will send > > a NCP connection request to allocate a connection slot. This is send to > > the server. So the router does not have to answer any NCP requests. > > Not all clients will RIP. Not all clients use the internal field > rather than the source address on the Nearest Server response (ie: > GetNearestServer can not be routed for these clients without the > router lying about its IPX network number in the IPX header). This may be true, but I haven't seen any that doesn't. All the versions of netx and the vlm's from Novell do it. > > I'm glad that the Nearest Server response is properly proxied, but this > will not fix all clients (especially 'remote reset' clients). To do > that, you will have to fake source address in the IPX header as well > as setting server address for the "nearest server" in the response. Maybe I don't understand your use of the term proxy, but I don't see the response to a SAP GetNearestServer request as proxy, because it is the job of a IPX router to be able to respond to SAP GetNearestServer and RIP requests. > > Like sliding windows in SPX, there is a major discrepancy between > specification and implementation. > > In addition, I would caution that a delay is necessary on router proxy > response to a GetNearestServer. Consider the case of: > > > ------------ ----------- o ---------- > | Netware | Net A | FreeBSD | x----| IPX | > | |---------| | | | | > | Server1 | | Router |----x N | Client | > ------------ ----------- | e ---------- > | t > | ------------ > | B | NetWare | > x----| | > | | Server2 | > o ------------ > > A "GetNearestServer" from "IPX client" will elicit a response both > from "FreeBSD Router" and "NetWare Server2". No it should not. Server1 isn't the nearest anymore, so the router should not respond to a GetNearestServer SAP request from the IPX client. > > You want the client to get the "NetWare Server2" response first; the > way to do this is to delay the response from "FreeBSD Router". There > is *not* a hop-count based "election" on nearest server preference; > it's whoever answers first. The Native NetWare server and the NWU > NetWare server both parameterize the ability to delay response. > > A local server is preferaable to a routed serve because of negotiated > packet sizes through routers dropping to 512. A bigger problem (performance wise) is the extra hop that is incurred for NCP. Burst mode isn't the whole answer to that. John -- John Hay -- John.Hay@csir.co.za
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