Messages in this thread | | | Date | Wed, 3 Feb 1999 14:33:11 +0000 (GMT/BST) | From | Mike Jagdis <> | Subject | Problems with 2.2.x IP routing etc. |
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1. The interface metric is ignored. It isn't even possible to set the metric on an interface never mind have it used for the auto-created routes. Is that intentional?
Consider, you have two machines A and B. A has a leased line to site C, B has a demand dialled ISDN link on hot stand by (i.e. configured and ready to dial). A's interface should be preferred over B's so B's is configured with a higher metric so it only gets traffic if A dies. Is that reasonable?
Diald uses a proxy interface with higher metric than the real interface. This simplifies changing things around as the link goes up and down (in theory :-) )
2. It is not possible to change the BROADCAST and POINTTOPOINT flags on an interface. This appears to be enforced in dev_change_flags in the kernel net code. It is not unreasonable for ordinary ethernet interfaces to be used as a fast p-t-p link between two systems in order to reduce traffic on the open network. (This implies that there must be a way to prefer the p-t-p link over the main net interface. Metric again?)
3. I don't know how to set a metric on a route with "ip". Nor does "ip" appear to display route metrics on routes created with "route" although "netstat" does.
4. Using an ippp interface I can manage to send out packets with a source address of 0.0.0.0.
The interface is configured with an ifconfig and a default route added through it with "route add default dev ippp0". "ip route" tells me:
10.1.254.1 dev ippp0 proto kernel scope link src 172.16.1.8 default dev ippp0 scope link
Packets routed *through* the local host are fine (as expected). Packets originating *from* the local host are sent on ippp0 correctly but have a source address of 0.0.0.0 (as reported by the remote host).
If I use "ip route add default dev ippp0 src 172.16.1.8" instead of using "route" "ip route" tells me:
10.1.254.1 dev ippp0 proto kernel scope link src 172.16.1.8 default dev ippp0 scope link src 172.16.1.8
Now locally originating packets go out with the correct source address. It looks like a problem with routing through a p-t-p but could be an ISDN problem (I haven't been able to reproduce the problem over async PPP for instance). This is the ISDN code from ftp.suse.com dated 990128 not the old stuff in the kernel.
N.B. I need to use "ip" to set the src addr on the default route but I can only set a metric if I use "route" :-(.
-- A train stops at a train station, a bus stops at a bus station. On my desk I have a work station... .----------------------------------------------------------------------. | Mike Jagdis | Internet: mailto:mike@roan.co.uk | | Roan Technology Ltd. | | | 54A Peach Street, Wokingham | Telephone: +44 118 989 0403 | | RG40 1XG, ENGLAND | Fax: +44 118 989 1195 | `----------------------------------------------------------------------'
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