Traceroute goes to lan1 instead of lan3.

[joe_91]

Team:

We have nclass running 11.0 with 5 NICs. lan1 and lan3 are primary cards with lan4 and lan5 as backup. lan1 and lan3 are in different subnets. When i do traceroute from an external box to lan3's ip it always goes to lan1. The whole purpose of creating lan3,lan5(using MC/SG) was to route the messageque traffic thru that interface.
1. Why would it go to lan1 instaed of lan3?

My system has currently only one default route specified wich is on lan1's subnet. Would that be the reason? Please explain how i will be able to use lan1 and lan3 effectively.

Thanks
Joe.

[Joaquin Gil de Vergara]

display me exit of

# netstat -in

and

# netstat -rn

thanks

[joe_91]

Here you go..

Thanks
Joe.

[Joaquin Gil de Vergara]

you have a problem in the routing table. Only appears routes to hosts. There isn't any route to any network..

please send me the files /etc/rc.config.d/netconf and /etc/networks

and an ifconfig of all interfaces

thanks

[joe_91]

Thanks again.
I have attached all that you required.

Thanks
Joe.

[Joaquin Gil de Vergara]

Change this in /etc/rc.config.d/netconf

INTERFACES
you can comment this

INTERFACE_NAME[0]=lan0
IP_ADDRESS[0]=""
SUBNET_MASK[0]=""
BROADCAST_ADDRESS[0]=""
INTERFACE_STATE[0]=""
DHCP_ENABLE[0]=0


IP_ADDRESS[3]=135.51.103.90
SUBNET_MASK[3]=255.255.255.224
INTERFACE_NAME[3]=lan3
BROADCAST_ADDRESS[3]=135.51.103.95
INTERFACE_STATE[3]=up
DHCP_ENABLE[2]=0
DHCP_ENABLE[3]=0

you must put the interface name here to bin to it!
INTERFACE_NAME[3]=lan3



ROUTES

# HEARTBEAT ROUTE
ROUTE_DESTINATION[0]=default
ROUTE_MASK[0]=""
ROUTE_GATEWAY[0]=135.51.27.1
ROUTE_COUNT[0]=1
ROUTE_ARGS[0]=""

and this is redundant... delete it and leave only the 0 instance
# DATA ROUTE TO ROUTER
ROUTE_DESTINATION[1]=default
ROUTE_MASK[1]=""
ROUTE_GATEWAY[1]=135.51.27.1
ROUTE_COUNT[1]=1
ROUTE_ARGS[1]=""
#






now re-start net services

# route -f (flush routing table)
# /sbin/init.d/net stop
# /sbin/init.d/net start


tell me if it works

[Kellogg Unix Team]

Interesting, I saw netstat -rn output and it looks OK to me! Can you also attach traceroute output from 2 clients from "different" subnets to this host?

I will be interested to know what's the final "netstat -rn" output looks like once this problem is resolved.

...Manjeet

[joe_91]

Hi:

I am not sure what to delete and what to enable. Can you tell me once again. Also if you do not have a default route will you be able to talk to the box at all?

Thanks
Joe.

[joe_91]

Traceroute output to lan3 from a diff. subnet.

Thanks
Joe.

[Sanjay_6]

Hi Joe,

You are seeing the traffic going out of lan1 because the default route is set the ip subnet for lan1.

You can setup multiple route to allow traffic flow through multiple interfaces.

Hope this helps.

Regds

[Todd Lehr]

Couple of questions:

1) what router is the lan3 subnet attached to, is it 172.30.2.90?
2) what is the ip address that the attached traceroute came from.
3) can you attach a traceroute from the nclass server to the that node (i.e. the other direction )

Also try disabling lan1 and see if you can ping or traceroute to the lan3 address from anywhere else

[Kellogg Unix Team]

Joe,

Try setting following ndd parameter and see if the behaviour changes. I have also sought help from my networking guy. It may be a feature of the router/switch -

ndd -set /dev/ip ip_strong_es_model 1

The document says that "packets destined for
the interface with IP address A will only be accepted on the interface with IP address A, and will be dropped if they start arriving on the interface with IP address B. In other words, Packets for a specicifc IP MUST come IN on the interface with that IP, otherwise they will be dropped."

You might want to read the whole document on ITRC (Doc ID# NETUXKBRC00005778)

Let us know your results.
...Manjeet

[Trevor Tung]

I have exactly the same problem.
I still can't figure out how to do a traceroute with Lan0, it always goes to LAN1:1

[Steven E. Protter]

In my opinion, the entire issue is that the default route is on lan1.

What I mean is that every route has a source and a destination. The source is set up in netconf

If you change the default route in /etc/rc.config.d/netconf to a lan3 source, you are going to route the way you want to.

It would seem also, that the structure of your network is somewhat circular. lan1 and lan3 seem to actually be on the same network. You've apparently used subnetting to make your machine think there are two different networks.

It seems that you can reach the same destination without the help of routers through either lan1 or lan3. Perhaps this is the way serviceguard is supposed to work, but thats what your setup tells me.

SEP