Routing tables are filling

[Mark Symmonds_1]

I am having a major problem with the routing tables on two HP-UX servers, running 10.20 and 11.00. The routing tables keep dynamically filling up with false UGHD or UGH flagged routes and it is causing clients to fail when attempting a connection. I am constantly having to run

netstat -rn | awk '$3=/UGHD/ {system ("route delete "$1" "$2" ")}'

in order to clear the junk entries.

Any ideas? I looked through everywhere and I do not appear to be running any dynamic routing daemons like routed. Also only the HP-UX servers are having these issues on the network. The Suns and Linux servers do not.

Thanks for any help, as I am getting frustrated.

[LucianoCarvalho]

hi,

Those entries are been created by any router in your network.
The routers uses icmp redirect to create these entries on HP-UX, when the router thinks there is a route better thant that the hp are using. You can disable icmp redirect on your router, so the entries will not be created any more. On a cisco router the command is "no ip redirect".

Regards

[LucianoCarvalho]

hi,

Those entries are been created by any router in your network.
The routers uses icmp redirect to create these entries on HP-UX, when the router thinks there is a route better thant that the hp are using. You can disable icmp redirect on your router, so the entries will not be created any more. On a cisco router the command is "no ip redirect".

Regards

[Mark Symmonds_1]

Isn't there a way to stop the HP-UX servers from adding the entries? Again the HP-UX servers are the only ones having this problem.

[LucianoCarvalho · Accepted solution]

there is no way to configure HP-UX to reject that, you have to configure the router to not send. But there is an IP Paremter that you can set up so the entries created by icmp redirect will be deleted in 5 seconds.
This is ip_ire_redirect_interval.
How To use:

Verify the current value:

ndd -get /dev/ip ip_ire_redirect_interval

Set the redirect interval to 5 second

ndd -set /dev/ip ip_ire_redirect_interval 5000

Additional Information
HP-UX 11.0
Minimum 5000 (5sec)
Maximum 600000 (10min)
The values is given in milliseconds.

best regards

[LucianoCarvalho]

there is no way to configure HP-UX to reject that, you have to configure the router to not send. But there is an IP Paremter that you can set up so the entries created by icmp redirect will be deleted in 5 seconds.
This is ip_ire_redirect_interval.
How To use:

Verify the current value:

ndd -get /dev/ip ip_ire_redirect_interval

Set the redirect interval to 5 second

ndd -set /dev/ip ip_ire_redirect_interval 5000

Additional Information
HP-UX 11.0
Minimum 5000 (5sec)
Maximum 600000 (10min)
The values is given in milliseconds.

best regards

[Mark Symmonds_1]

When I try that I get:

# ndd -set /dev/ip ip_ire_redirect_interval 5000
operation failed, Invalid argument

Thanks for your help!

[LucianoCarvalho]

I got the same error too. I realized that the minimum value accepted is 60000 or 1 minute.

I forgote to say about nddconf file.
You have to configure an entry in /etc/rc.config.d/nddconf file (if it doesn't existe you can copy from /usr/newconfig/etc/rc.config.d) or after reboot the value will come back to the default value.
Example of an entry:

TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_ire_redirect_interval
NDD_VALUE[0]=6000

regards

[Mark Symmonds_1]

Thank you. That looks like it is helping a little, but I still think HP needs to create a patch to be able to turn this off.

[Mark Symmonds_1]

My networking folks say ICMP redirect is not turned on the routers.