topic Re: IP SLA problems in Routing and SD-WAN

IP SLA problems

rasoftware — Sun, 03 Mar 2019 19:50:38 GMT

have this config

ip sla 1

icmp-echo 62.6.200.5

timeout 1000

threshold 2

frequency 3

ip sla schedule 1 life forever start-time now

track 100 rtr 1 reachability

ip route 0.0.0.0 0.0.0.0 "our-next-hop" track 100

ip route 0.0.0.0 0.0.0.0 Dialer0 254

ip nat inside source route-map ispA interface FastEthernet0 overload

ip nat inside source route-map ispB interface Dialer0 overload

access-list 40 remark IPs for NAT policy

access-list 40 permit 192.0.0.0 0.255.255.255

access-list 101 permit icmp any host 62.6.200.5 echo

route-map LOCAL_POLICY permit 10

match ip address 101

set interface FastEthernet0

route-map ispB permit 10

match ip address 40

match interface Dialer0

route-map ispA permit 10

match ip address 40

match interface FastEthernet0

The track doesn seem to work, when I have default route to metric 1 and no track it works.

I have this config working where I have two DSL ports but this has 1 DSL and 1 FE.

Will this work?

Re: IP SLA problems

pkhatri — Thu, 23 Feb 2006 13:35:04 GMT

Hi,

I presume you can do a ping to 62.6.200.5 without any problems.

Have you got the following configured:

ip local policy route-map LOCAL_POLICY

Paresh

Re: IP SLA problems

rasoftware — Thu, 23 Feb 2006 13:46:33 GMT

Yes ip local policy route-map LOCAL_POLICY .

If I change the route to a normal static I can ping that address.

Re: IP SLA problems

rasoftware — Thu, 23 Feb 2006 13:51:40 GMT

I have attached a more complete config

Re: IP SLA problems

attrgautam — Thu, 23 Feb 2006 14:14:37 GMT

Have you started the IP sla using

ip sla schedule 1 life forever start-time now

If yes, can you show the output of

sh ip sla statistics and sh track

Re: IP SLA problems

rasoftware — Thu, 23 Feb 2006 14:34:23 GMT

Looks like it not working, I have also tried another IP as the ping address:

Track 100

Response Time Reporter 1 reachability

Reachability is Down

3 changes, last change 01:38:32

Latest operation return code: Timeout

Tracked by:

STATIC-IP-ROUTING 0

Track 100

Response Time Reporter 1 reachability

Reachability is Down

3 changes, last change 01:38:32

Latest operation return code: Timeout

Tracked by:

STATIC-IP-ROUTING 0

rasoft-gw#sh ip sla stat

Round Trip Time (RTT) for Index 1

Latest RTT: NoConnection/Busy/Timeout

Latest operation start time: *14:28:29.339 PCTime Thu Feb 23 2006

Latest operation return code: Timeout

Number of successes: 0

Number of failures: 54

Operation time to live: Forever

Re: IP SLA problems

pkhatri — Thu, 23 Feb 2006 20:51:23 GMT

Hi,

Can you change your route-map to look like below:

route-map LOCAL_POLICY permit 10

match ip address 101

set ip next-hop 195.x.x.x

Make 195.x.x.x the same as what you have in your static route and re-try your tests

Hope that helps - pls rate the post if it does.

Paresh

Re: IP SLA problems

rasoftware — Fri, 24 Feb 2006 09:51:37 GMT

Thanks Paresh - helped me out yet again! Much appreciated

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 09:38:53 GMT

Still having a little trouble with this. The FastEthernet primary WAN keeps declaring the route down.

Track 100

Response Time Reporter 1 reachability

Reachability is Down

1 change, last change 1w0d

Latest operation return code: Timeout

Tracked by:

STATIC-IP-ROUTING 0

and

Round Trip Time (RTT) for Index 1

Latest RTT: NoConnection/Busy/Timeout

Latest operation start time: *09:35:09.847 PCTime Wed Mar 8 2006

Latest operation return code: Timeout

Number of successes: 0

Number of failures: 48

Operation time to live: Forever

When it first boots it works for a while, I dont know why it switchs to the fail over link. It also never switches back.

I have tried using a different destination ICMP address but its the same.

I post complete config for clarity.

Re: IP SLA problems

pkhatri — Wed, 08 Mar 2006 10:13:06 GMT

Could you try the following and post the output:

debug ip policy

ping 217.32.63.202

Thanks,

Paresh

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 10:14:52 GMT

Ok I think i have spotted my own problem:

Timeout set to 2 (chaned 1500)

no frequency set

I have changed these will post back if still unreliable

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 13:50:27 GMT

It does now fail over, when i disabled FE as test it switched to backup ADSL. However, it has not switched back.

I run you command (both links available - using dialer:

rasoft-gw#debug ip policy

Policy routing debugging is on

rasoft-gw#ping 217.32.63.202

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 217.32.63.202, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

When I re-run (after a reload I get)

rasoft-gw#sh track

Track 100

Response Time Reporter 1 reachability

Reachability is Up

2 changes, last change 00:00:24

Latest operation return code: Over threshold

Latest RTT (millisecs) 16

Tracked by:

STATIC-IP-ROUTING 0

rasoft-gw#debug ip policy

Policy routing debugging is on

rasoft-gw#ping 217.32.63.202

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 217.32.63.202, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 16/19/20 ms

Doing sh ip route indicates dialer is still primary despite FE being up:

S* 0.0.0.0/0 is directly connected, Dialer0

i also notice that non of the policy based routes are being used:

rasoft-gw#sh route

route-map LOCAL_POLICY, permit, sequence 10

Match clauses:

ip address (access-lists): 101

Set clauses:

ip next-hop 195.172.169.x

Policy routing matches: 1913 packets, 122612 bytes

route-map ispB, permit, sequence 10

Match clauses:

ip address (access-lists): 40

interface Dialer0

Set clauses:

Policy routing matches: 0 packets, 0 bytes

route-map ispA, permit, sequence 10

Match clauses:

ip address (access-lists): 40

interface FastEthernet0

Set clauses:

Policy routing matches: 0 packets, 0 bytes

Re: IP SLA problems

pkhatri — Wed, 08 Mar 2006 19:46:03 GMT

One other thing, mate...

Change your route-map so that it looks like this:

route-map LOCAL_POLICY permit 10

match ip address 101

set ip next-hop 195.172.169.99

set interface null0

Paresh

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 21:39:57 GMT

thanks Paresh, I have made the change and will monitor.

Whats the significance of the null0?

Also, I found this which was helped me for anyone looking a PBR.

http://www.cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html#wp1071380

Re: IP SLA problems

pkhatri — Wed, 08 Mar 2006 22:01:32 GMT

The 'interface null0' statement means that the ping packet will only be sent out the specified IP next-hop. If that next-hop is down, it will be dropped. The point of this is to ensure that the ping only succeeds when sent out through the interface being monitored. There could be other ways of getting out but we are only interested in monitoring this interface.

Hope that helps - pls rate the post if it does.

Paresh

Re: IP SLA problems

pkhatri — Wed, 08 Mar 2006 22:47:05 GMT

One more thing, dude...

When you did the 'debug ip policy' followed by the ping, were you telnet'ed into the router ? If so, could you repeat that but enter the 'term mon' command first ? That will ensure that the debug output is displayed on your terminal window.

Paresh

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 22:47:18 GMT

I added the null0.

If i shutdown the fastethernet0 (primary) and bring it back up, the route doesn not come back?

Do I need to define the null0 interface?

I think its trying to ping the target which the sla monitor requires, but because the dialer router is remaining and the set next hop is not reachable becuase of the set, its dropping the icmp and the router is never coming back.

The next-hop address is our gateway to the isp, same subnet the fastethernet0 so I thinks that correct.

Dialer interface is separate ISP.

Seems strange cos it worked well when I had two dialers and just did "set interface dialer" and matched ip of icmp target.

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 22:58:24 GMT

I added the null0.

If i shutdown the fastethernet0 (primary) and bring it back up, the route doesn not come back?

Do I need to define the null0 interface?

The next-hop address is our gateway to the isp, same subnet the fastethernet0 so I thinks that correct.

Dialer interface is separate ISP.

Seems strange cos it worked well when I had two dialers and just did "set interface dialer" and matched ip of icmp target.

Re: IP SLA problems

rasoftware — Wed, 08 Mar 2006 23:03:08 GMT

Debug as requested

217.32.63.202 - is the icmp "target" for reliable routing.

*Mar 8 22:56:21.879: IP: s=81.149.144.41 (local), d=217.32.63.202, len 64, poli

cy match

*Mar 8 22:56:21.879: IP: route map LOCAL_POLICY, item 10, permit

*Mar 8 22:56:21.879: IP: s=81.149.144.41 (local), d=217.32.63.202 (FastEthernet

0), len 64, policy routed

*Mar 8 22:56:21.879: IP: local to FastEthernet0 195.172.169.17no

*Mar 8 22:56:23.231: IP: s=81.149.144.41 (local), d=81.179.89.80, len 576, poli

cy rejected -- normal forwarding

Re: IP SLA problems

pkhatri — Wed, 08 Mar 2006 23:08:26 GMT

Would you be able to re-attach your config ? I can't open the one you attached earlier... some issue with the NetPro server, I guess.

Paresh