[j-nsp] ARP on unnumbered interfaces
Mihai
mihaigabriel at gmail.com
Sun Jan 11 06:56:46 EST 2015
No, because I have different prefixes routed through one unnumbered
interface. The same situation with ARP will occur in your setup.
routing-options {
static {
route 20.20.20.2/32 {
qualified-next-hop ge-1/1/8.55;
}
route 10.10.10.5/32 {
qualified-next-hop ge-1/1/8.55;
}
route 11.11.11.3/32 {
qualified-next-hop ge-1/1/8.55;
}
}
etc...
I am starting to think that this is an 'unsupported' configuration.
On 01/11/2015 12:08 PM, Dave Bell wrote:
> Would the preferred-source-address statement work in your situation?
>
> From the link Madood posted:
> interfaces {
> lo0 {
> unit 0 {
> family inet {
> address 2.2.2.1/32 <http://2.2.2.1/32>;
> address 3.3.3.1/32 <http://3.3.3.1/32>;
> }
> }
> }
> }
> interfaces {
> ge-4/0/0 {
> unit 0 {
> family inet {unnumbered-address lo0.0 preferred-source-address
> 3.3.3.1;
> }
> }
> }
> }
>
> On 11 Jan 2015 07:06, "Mihai" <mihaigabriel at gmail.com
> <mailto:mihaigabriel at gmail.com>> wrote:
>
> Thank you for your response.If the document is true,then all ARPs
> should be originated with the primary address and as you can see
> this is not the case (tested on multiple platforms with different
> codes,Cisco included).
> One workaround i found is to delete/add the static route,but it
> doesn't work in all cases.
>
>
> On 01/11/2015 02:13 AM, Masood Ahmad Shah wrote:
>
> AFAIK, router uses the preferred source address when it is
> configured
> for an unnumbered Eth interface, for arp requests and replies. arp
> requests need to match the preferred source address, which is by
> default
> primary interfaces
>
> lo0 {
> unit 55 {
> family inet {
> address 5.5.5.5/32 <http://5.5.5.5/32>
> <http://5.5.5.5/32> { //That
> would be this in your case.
> primary;
> }
> address 10.10.10.1/24 <http://10.10.10.1/24>
> <http://10.10.10.1/24>;
> address 20.20.20.1/24 <http://20.20.20.1/24>
> <http://20.20.20.1/24>;
> }
> }
> }
>
> More here:
> http://www.juniper.net/__documentation/en_US/junos13.2/__topics/usage-guidelines/__interfaces-configuring-an-__unnumbered-interface.html
> <http://www.juniper.net/documentation/en_US/junos13.2/topics/usage-guidelines/interfaces-configuring-an-unnumbered-interface.html>
>
> Cheers,
> Masood
>
> On Sun, Jan 11, 2015 at 2:34 AM, Mihai <mihaigabriel at gmail.com
> <mailto:mihaigabriel at gmail.com>
> <mailto:mihaigabriel at gmail.com
> <mailto:mihaigabriel at gmail.com>__>> wrote:
>
> Hello,
>
> After the migration of a large network from a Cisco 7600 to a
> MX104 a lot of users started to have random problems with their
> connection.
> The setup is based on unnumbered interfaces and /32 static
> routes
> through IFLs.
> Basically, all clients with Cisco routers will have at
> some point a
> missing ARP entry for their default gateway because the MX is
> changing the ARP source address from the gw_addr to the primary
> address.On Cisco i see the well known 'wrong cable' error.
> Does anyone have a clue why is this happening beside a bug?
> I've
> made some tests on MX960,MX480 and MX5 and didn't see this
> behavior.
> This is a lab simulation:
>
>
> mx# show
>
> interfaces {
> ge-1/1/8 {
> unit 55 {
> vlan-id 55;
> proxy-arp unrestricted;
> family inet {
> unnumbered-address lo0.55;
> }
> }
> unit 56 {
> vlan-id 56;
> proxy-arp unrestricted;
> family inet {
> unnumbered-address lo0.55;
> }
> }
> }
> lo0 {
> unit 55 {
> family inet {
> address 5.5.5.5/32 <http://5.5.5.5/32>
> <http://5.5.5.5/32> {
> primary;
> }
> address 10.10.10.1/24
> <http://10.10.10.1/24> <http://10.10.10.1/24>;
> address 20.20.20.1/24
> <http://20.20.20.1/24> <http://20.20.20.1/24>;
> }
> }
> }
> }
> routing-options {
> static {
> route 20.20.20.2/32 <http://20.20.20.2/32>
> <http://20.20.20.2/32> {
> qualified-next-hop ge-1/1/8.55;
> }
> route 10.10.10.2/32 <http://10.10.10.2/32>
> <http://10.10.10.2/32> {
> qualified-next-hop ge-1/1/8.56;
> }
> }
> router-id 5.5.5.5;
> }
>
> mx> monitor traffic interface ge-1/1/8.55 detail no-resolve
> matching arp
> Address resolution is OFF.
> Listening on ge-1/1/8.55, capture size 1514 bytes
>
> 17:28:11.105586 Out arp who-has 20.20.20.2 tell 20.20.20.1
> 17:28:11.106100 In arp reply 20.20.20.2 is-at
> 00:1e:4a:fc:44:84
> 17:29:20.504891 Out arp who-has 20.20.20.2 tell 20.20.20.1
> 17:29:20.505375 In arp reply 20.20.20.2 is-at
> 00:1e:4a:fc:44:84
> 17:30:30.104188 Out arp who-has 20.20.20.2 tell 20.20.20.1
> 17:30:30.104632 In arp reply 20.20.20.2 is-at
> 00:1e:4a:fc:44:84
>
> .....
>
> 17:53:01.790690 Out arp who-has 20.20.20.2 tell 5.5.5.5
> 17:54:05.690056 Out arp who-has 20.20.20.2 tell 5.5.5.5
>
> Thanks!
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