topic Re: Unremoveble route in Operating System - HP-UX

Unremoveble route

GabrielHuerta — Wed, 29 Oct 2008 10:51:27 GMT

Hi guys,
I'm trying to remove a route but it's imposible.
The route seems to be removed but when i issue a ping to the hosts, the route appears again.
The route to be romove is 172.31.207.100/255.255.255.255
Any idea?
I post the trace of the events:
root@ctcdwp1:/>netstat -rnv
Routing tables
Dest/Netmask Gateway Flags Refs Use Interface Pmtu
127.0.0.1/255.255.255.255
127.0.0.1 UH 0 26845 lo0 4136
10.88.21.45/255.255.255.255
10.88.21.45 UH 0 119986980 lan0 4136
172.31.207.100/255.255.255.255
10.88.21.1 UGH 0 0 lan0 1500
172.31.207.104/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
172.31.207.109/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
10.88.21.0/255.255.255.0
10.88.21.45 U 2 0 lan0 1500
127.0.0.0/255.0.0.0 127.0.0.1 U 0 0 lo0 4136
172.16.0.0/255.240.0.0 10.88.21.2 UG 0 0 lan0 1500
default/0.0.0.0 10.88.21.1 UG 0 0 lan0 1500
root@ctcdwp1:/>route delete host 172.31.207.100 10.88.21.1
delete host 172.31.207.100: gateway 10.88.21.1
root@ctcdwp1:/>netstat -rnv
Routing tables
Dest/Netmask Gateway Flags Refs Use Interface Pmtu
127.0.0.1/255.255.255.255
127.0.0.1 UH 0 26845 lo0 4136
10.88.21.45/255.255.255.255
10.88.21.45 UH 0 119986980 lan0 4136
172.31.207.104/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
172.31.207.109/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
10.88.21.0/255.255.255.0
10.88.21.45 U 2 0 lan0 1500
127.0.0.0/255.0.0.0 127.0.0.1 U 0 0 lo0 4136
172.16.0.0/255.240.0.0 10.88.21.2 UG 0 0 lan0 1500
default/0.0.0.0 10.88.21.1 UG 0 0 lan0 1500
root@ctcdwp1:/>ping 172.31.207.100
PING 172.31.207.100: 64 byte packets

----172.31.207.100 PING Statistics----
1 packets transmitted, 0 packets received, 100% packet loss
root@ctcdwp1:/>netstat -rnv
Routing tables
Dest/Netmask Gateway Flags Refs Use Interface Pmtu
127.0.0.1/255.255.255.255
127.0.0.1 UH 0 26845 lo0 4136
10.88.21.45/255.255.255.255
10.88.21.45 UH 0 119986980 lan0 4136
172.31.207.100/255.255.255.255
10.88.21.1 UGH 0 0 lan0 1500
172.31.207.104/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
172.31.207.109/255.255.255.255
10.88.21.2 UGH 0 0 lan0 1500
10.88.21.0/255.255.255.0
10.88.21.45 U 2 0 lan0 1500
127.0.0.0/255.0.0.0 127.0.0.1 U 0 0 lo0 4136
172.16.0.0/255.240.0.0 10.88.21.2 UG 0 0 lan0 1500
default/0.0.0.0 10.88.21.1 UG 0 0 lan0 1500

netstat >show the route
route delete> delete the route
ping to the host>unreachable
netstat >show the route again

comor!!!!!!

Re: Unremoveble route

Suraj K Sankari — Wed, 29 Oct 2008 11:12:34 GMT

Hi,

Did you restart the net after deleting the route.

#inetd -c ( restart the route

Suraj

Re: Unremoveble route

GabrielHuerta — Wed, 29 Oct 2008 11:20:23 GMT

that does not work,
thanks

Re: Unremoveble route

Matti_Kurkela — Wed, 29 Oct 2008 11:48:22 GMT

Looks like your gateway (10.88.21.2) is sending ICMP Redirect messages if it thinks there is a more direct route to destination.

See this thread:
http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=49359

Summary:
If your gateway is a Cisco router, you should configure it with "no ip redirect" command to disable ICMP Redirect messages.

There seems to be no way to make HP-UX completely ignore ICMP Redirect messages at the OS level, but you might install and configure ipfilter software to filter out the redirect messages before they are processed. There are some other workarounds too.

MK

Re: Unremoveble route

Jim Keeble — Thu, 30 Oct 2008 12:20:14 GMT

You might try this :

# ndd -h ip_ire_redirect_interval

ip_ire_redirect_interval:

All routing table entries resulting from ICMP "Redirect"
messages are deleted after this much time has elapsed,
whether or not the entry has been recently used. Setting
ip_ire_redirect_interval to 0 causes
- all existing routing table entries specifying
a redirect to be deleted after the previous value of
ip_ire_redirect_interval has elapsed and
- no further routing entries are created for the future
ICMP REDIRECT messages.
Processing of ICMP REDIRECT messages can be enabled again
by setting ip_ire_redirect_interval to a non-zero, positive
value.
[0, -] Default: 300000 (5 minutes)