Gateway / Routing Problem

[Peter Reuschlein]

Hey everybody,

i have a little Gateway / Routing Problem with one of our servers and i can´t figure out what the problem is.
The situation: I moved a HPUX 11.0 server from 10.16.70.11 to another net (10.16.192.14)
I changed the default route to 10.16.192.1 and changed the /etc/rc.config.d/netconf to
ROUTE_DESTINATION[0]=default
ROUTE_MASK[0]=""
ROUTE_GATEWAY[0]=10.16.192.1
ROUTE_COUNT[0]=1
ROUTE_ARGS[0]=""

netstat -rn shows
phxsvr02:/etc/rc.config.d (phoenix) $ netstat -rn
Routing tables
Dest/Netmask Gateway Flags Refs Use Interface Pmtu
127.0.0.1 127.0.0.1 UH 0 71817 lo0 4136
10.16.192.14 10.16.192.14 UH 0 60980 lan0 4136
10.16.192.0 10.16.192.14 U 2 0 lan0 1500
127.0.0.0 127.0.0.1 U 0 0 lo0 4136
default 10.16.192.1 UG 0 0 lan0 1500
phxsvr02:/etc/rc.config.d (phoenix) $



The misterious thing ist -> when i reboot the server. I can use it from an other subnet without problems for around 30sec - 1 min. Then it stops replying to pings and i can´t login with ssh anymore. When i jump to a server in the same subnet the server still replies and i can login over that one.

Any1 knows how that could be, and how i can fix it?

thanks
P

[T G Manikandan · Accepted solution]

Disable dead gateway detection

What is the output of
#ndd -get /dev/ip ip_ire_gw_probe

#ndd -set /dev/ip ip_ire_gw_probe 0

Make the changes persistent in nddconf

[Peter Reuschlein]

the reply
phxsvr02:/etc/rc.config.d (root) $ ndd -get /dev/ip ip_ire_gw_probe
1

so i set it to 0 like you said
then i insert into nddconf

TRANSPORT_NAME[0]=tcp
NDD_NAME[0]=ip_ire_gw_probe
NDD_VALUE[0]=0

TRANSPORT_NAME[0]=udp
NDD_NAME[0]=ip_ire_gw_probe
NDD_VALUE[0]=0



hope thats ok?

i brought the interface down and up again
(ifconfig lan0 down / up)

still now working -> don´t wanna restart atm
Another service or something to restar

[The Real MD]

This is 100% definately the detect dead gateway setting. Your machine is autonomously deciding that it will stop trying to route traffic to its default gateway if it cant ping it. I had the same issue routing through a firewall took me a while to find an answer.

The above config changes will sort you out.

dont forget to reboot.

Regards

Martin.

[Ron Kinner]

NOT:

TRANSPORT_NAME[0]=tcp
NDD_NAME[0]=ip_ire_gw_probe
NDD_VALUE[0]=0

TRANSPORT_NAME[0]=udp
NDD_NAME[0]=ip_ire_gw_probe
NDD_VALUE[0]=0


But:

TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_ire_gw_probe
NDD_VALUE[0]=0

Also it helps to remove the default gateway and readd it. Seems that once you turn off dead gateway detection the process that removes a gateway from the dead list stops too.

Did you run a second ndd -get to check that it had worked?

Ron

[Peter Reuschlein]

sorry for missing answer ->
it works already
(seems also that ip and udp from me worked)

thx & greetz

[Ron Kinner]

I think it only reads ndd during a reboot or perhaps with an inet -c so I would advise you to change it to use the ip version I gave you.

Ron