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- Newsgroups: comp.dcom.sys.cisco
- Path: sparky!uunet!boulder!recnews
- From: Peter Elford <P.Elford@aarnet.edu.au>
- Subject: Re: Variable subnet masks
- Message-ID: <722246079.5967@news.Colorado.EDU>
- Sender: news
- Date: 20 Nov 92 16:18:01 +1100
- Approved: news
- X-Note1: mail msgid was <9211200518.AA10780@jatz.aarnet.edu.au>
- X-Note2: message-id generated by recnews
- Lines: 54
-
-
- >Date: Thu, 19 Nov 1992 21:30:04 -0500
- >From: henryc@oar.net
- >
- >No, you need to be running at least 9.1 to support VLSM.
-
- I have a CS-516 running the Interim release of 9.1 and it's
- kind of weird to see this:
-
- GS>sh ip rout
-
- Codes: I - IGRP derived, R - RIP derived, H - HELLO derived, O - OSPF derived
- C - connected, S - static, E - EGP derived, B - BGP derived
- * - candidate default route, IA - OSPF inter area route
- E1 - OSPF external type 1 route, E2 - OSPF external type 2 route
-
- Gateway of last resort is 139.130.22.1 to network 0.0.0.0
-
- 139.130.0.0 is variably subnetted, 5 subnets, 2 masks
- S 139.130.0.0 255.255.0.0 [1/0] via 139.130.22.1
- C 139.130.18.0 255.255.255.192 is directly connected, Async2
- C 139.130.22.0 255.255.255.192 is directly connected, Ethernet0
- C 139.130.98.0 255.255.255.192 is directly connected, Async3
- R 139.130.116.0 255.255.255.192
- [120/1] via 139.130.22.1, 0:00:14, Ethernet0
-
- Also, something that threw me initially, is that with VLSM, the
- default-network command for setting a subnet default goes away. This is
- a tail router that is connected to a piece of our network via a loaded
- 48K link, so rather than send routes for all 81 subnets of 139.130, we
- normally use a subnet default route. Under 9.1, if you enter
-
- ip default-network 139.130.22.0
-
- you get in your configuration
-
- ip route 139.130.0.0 255.255.0.0 139.130.22.0
-
- Note the subnet mask, and the gateway address (the later is *wrong*).
-
- I replaced this with
-
- ip route 139.130.0.0 255.255.0.0 139.130.22.1
-
- (the gateway address is now a host address, rather than a subnet address)
-
- This works just fine.
-
- Peter Elford, e-mail: P.Elford@aarnet.edu.au
- Network Co-ordinator phone: +61 6 249 3542
- Australian Academic Research Network fax: +61 6 249 1369
- c/o, Computer Services Centre pager: +61 6 245 3035
- Australian National University post: GPO Box 1142
- Canberra, AUSTRALIA Canberra ACT 2601
-