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Advisor

Dual Internet Link load-balancing,traffic from Outside Issue

Hi,

This evening I can't but tomorrow evening it's possible at 9 PM brussels time, just let me know or tell me which time tomorrow will suit you.

Regards.

Alain

Don't forget to rate helpful posts.
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Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

Hi,

If we change topo like this maybe can resolve my problem:

But i don't have test yet, theoretically i think can be done.

Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

Have you test it yet?

I have the same question on my network

Thanks.

Rising star

Dual Internet Link load-balancing,traffic from Outside Issue

Mohamed,

If I configure both the interface PBR and also the ip local PBR which one would take priority?

HTH

Kishore

Rising star

Dual Internet Link load-balancing,traffic from Outside Issue

Hi Kishore,

There is no Priority in this Context.

The Difference is that (Local Policy/PBR) as the name implies is local to the Router, Traffic originated by the router itself is policy based routed, While the (PBR) is a Policy that matches all datagrams hiting an interface (Incoming) Traffic that hits an interface is subject to the PBR.

Regards,

Mohamed

Rising star

Re: Dual Internet Link load-balancing,traffic from Outside Issue

Hi Mohamed,

Thnks for the reply. I understand that. What I was asking was if I had both of them configured which of them will be used.

So, lets take this thread for eg: traffic is destined to the router so will the router use the policy on the interface or will it use the local policy PBR to reply back

Regards

Kishore

Advisor

Dual Internet Link load-balancing,traffic from Outside Issue

Hi Kishore,

it will use the local PBR policy not the other one in this case.

Regards.

Alain

Don't forget to rate helpful posts.
Rising star

Dual Internet Link load-balancing,traffic from Outside Issue

Thanks Alain. Any doco or link to point out what you mentioned. Not that I dont trust you but If I am asked by someone else then I can send them the same link

BTW, please check your PM

Regards

Kishore

Advisor

Dual Internet Link load-balancing,traffic from Outside Issue

Hi kishore,

I'll answer you tomorrow.

Regards.

Alain

Don't forget to rate helpful posts.
Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

I did Lab it up...  So to speak, or needed this same function on my router, so I tested both ways:

Code :      C2900-UNIVERSALK9-M), Version 15.1(4)M3

Scenario : I have a default gateway on my 2900 router through an ASA firewall.  I need to be able to SSH to the router, on an external interface, but it uses the ASA for default traffic, so I can either VPN in, and then SSH or implement this work around.

Work Arround Implemented :

ip access-list extended External_Manager_Traffic
   permit tcp host 30.20.10.1 eq 22 any
   permit icmp host 30.20.10.1 any echo-reply

!

route-map External_Management permit 10
match ip address External_Manager_Traffic
set ip next-hop 30.20.10.2     ! ISP Gateway

!

ip route 0.0.0.0 0.0.0.0 10.31.120.254

!

interface GigabitEthernet0/1
description Sip and VPN interface
ip address 30.20.10.1 255.255.255.0
!
ip local policy route-map External_Management

I tried putting the policy-map on the gig 0/1 interface, but it didn't work.  The router hasn't yet decided the traffic needs to go anywhere when it hits the interface.  It then is sent to CPU and CPU uses routing table to lookup and send to default route.  By Adding the Local Policy route-map we tell the CPU to apply this route map to traffic exiting the CPU.  In this case we bypass the routing table and set the next hop, which triggers routing table lookup for the next hop rather than for the ultimate destination.

Brian S. Turner
CCIE 6145
Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

Could you paste a diagram with the IPs?

I think the outbound SSH traffic (to Internet) response don´t use the 22 port, so this traffic doesn´t match the ACL and won´t be routed through the IP 30.20.10.2 necessarily.

To develop this solution is neccessary identify the outbound traffic to create an appropiate ACL/route, o set a rule to guarantee outbound traffic (ssh response) will be forwarded through que same interface/ISP it was received (ssh request).

I´ve the same problem with a pptp VPN.

Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

ip access-list extended External_Manager_Traffic

     permit tcp host 30.20.10.1 eq 22 any

     permit icmp host 30.20.10.1 any echo-reply

My ACL here clearly states to permit return traffic for SSH sessions towards 30.20.10.1.  It doesn't state traffic destined to 30.20.10.1 on port 22, it says RETURN Traffic

Correct version as I have it:

          permit tcp host 30.20.10.1 eq 22 any

Incorrect verion as you describe wouldn't work :

          permit tcp host 30.20.10.1 any eq 22

The port 22 I'm matching on is for the Source Host TCP port, not the destination host TCP port.

Its working in production using this config.  I really don't have time to do a drawing.  The IP addresses I've changed from production for obvious reasons.

Brian S. Turner
CCIE 6145
Beginner

Re: Dual Internet Link load-balancing,traffic from Outside Issue

I gather based on your answer using the configuration and schema attached, the return traffic (vpn response) should always go back through the router

2. Is that so?

VPN with load balancer.jpg

LoadBalancer#

ip access-list extended External_VPN_access

   permit tcp host 192.168.1.150 eq 1723 any

   permit icmp host 192.168.1.150 any echo-reply

!

route-map External_VPN permit 10

match ip address External_VPN_access

set ip next-hop 192.168.1.101

!

ip local policy route-map External_VPN

Beginner

Re: Dual Internet Link load-balancing,traffic from Outside Issue

1. in your scheme, the traffic destination is not the router.  so a local policy map, will never match traffic sourced from another device, even if it passes through the routrer.  you would need a normal policy map on the interface. to match that traffic.  remember that ip local policy map only affects traffic from the cpu of the router itself, which is why it works from SSH, to the router, but not pptp through the router.

there are many gotcha's in your design, and it is very different than the topic here.  you should describe what you want to do, and what challenges you are facing with it.  i dont really see that the router has much of a roll there

Brian S. Turner
CCIE 6145
Beginner

Dual Internet Link load-balancing,traffic from Outside Issue

The scheme is the network that I have installed in my workplace, and currently is working perfectly except for the issue of outside access through the VPN, which I think can be solved with a normal policy map as you say. My problem is very similar to the topic.


The role of the Cisco router in the network is to balance the load between the 2routers "fools" of ISPs, and providing failover. It does only static routing with CEF and without Nat, and a single interface connected to the network, which makes both input and output. Behind the balancer is a server that is the gateway and dhcp server (among other things) on my local network. I need the balancer is in-same ethernet segment as the other routers and configure the server to alternate routes on the server directly to the ISP's routers

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