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New Member

communication issue

dear friends,

there is a linux box with one of its interface ip address 172.18.104.210 == vlan 18

it has a route like this

172.16.0.0/12 next hop 172.18.104.254

the mac address, arp entry and interface are all looking good..

ping from vlan 18 works fine..

We have intermittent issues..ping from different vlan does not work until i intitiate ping from core switch or router.atleast 1 ping from core switch or router is required for the linux box to respond to ping from different vlans. attached a screen shot..

please let me know if you can help

below is some outputs

Proxy and icmp redirect are already enabled on vlan 18 and vlan 10 interfaces..

SWITCHSTACk1#show ip int vl 18 | i Proxy | ICMP

  Proxy ARP is enabled

  Local Proxy ARP is disabled

  ICMP redirects are always sent

  ICMP unreachables are always sent

  ICMP mask replies are never sent

SWITCHSTACk1#show ip int vl 10 | i Proxy | ICMP

  Proxy ARP is enabled

  Local Proxy ARP is disabled

  ICMP redirects are always sent

  ICMP unreachables are always sent

  ICMP mask replies are never sent

SWITCHSTACk1#show run int vl 18

Building configuration...

Current configuration : 140 bytes

!

interface Vlan18

ip address 172.18.104.253 255.255.255.0

standby 18 ip 172.18.104.254

standby 18 priority 105

standby 18 preempt

end

SWITCHSTACk1#show run int vl 10

Building configuration...

Current configuration : 136 bytes

!

interface Vlan10

ip address 10.1.104.253 255.255.254.0

standby 10 ip 10.1.104.254

standby 10 priority 105

standby 10 preempt

end

Right now, I cannot ping the linux box address.

C:\Users\vinayaka_raman>ping 172.18.104.210

Pinging 172.18.104.210 with 32 bytes of data:

Request timed out.

Request timed out.

Request timed out.

Request timed out.

Ping statistics for 172.18.104.210:

    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

After initiating a ping from the core switch, I can ping.

SWITCHSTACk1#ping 172.18.104.210

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.18.104.210, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/16 ms

C:\Users\vinayaka_raman>ping 172.18.104.210

Pinging 172.18.104.210 with 32 bytes of data:

Reply from 172.18.104.210: bytes=32 time=57ms TTL=60

Reply from 172.18.104.210: bytes=32 time=52ms TTL=60

Reply from 172.18.104.210: bytes=32 time=56ms TTL=60

Reply from 172.18.104.210: bytes=32 time=55ms TTL=60

Ping statistics for 172.18.104.210:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

    Minimum = 52ms, Maximum = 57ms, Average = 55ms

--

Regards
Vinayak       

Regards Vinayak
Everyone's tags (1)
6 REPLIES
Purple

communication issue

Hi,

Can you post your topology and where are located the linux box, the core switch and the box from where you are pinging.

Regards

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.
Hall of Fame Super Blue

communication issue

Vinayak

Can you explain how things are connected ie.

1) the linux box is in vlan 18 and has an IP of 172.18.104.210

2) there ia switch with a vlan 18 interface using a virtual IP of  172.18.104. Is this the default gateway of the linux box. If so why have you added that route because it will send traffic for 172.16.0.0/12 to it's default gateway anyway ?

By the way 172.16.0.0/12 overlaps with 172.18.104.210 - is this intentional ?

3)  When you say you cannot ping it, from what IP are you pinging from ?

4) Where is that IPs default gateway ?

So which devices have the L3 interfaces for vlan 18 and the vlan your pinging from. If they are different how are they interconnected.

Jon

New Member

Re: communication issue

1) the linux box has many interfaces and one of them is on vlan 18

2) yes,,switch ip is 172.18.104.254 and there is no gateway configured on the linux box for this interface

yes..it is interntional

3) i am trying to ping from remote site

4) on the core switch

5) both core switch and router has l3 interfaces..

Regards
Vinayak

Regards Vinayak
Hall of Fame Super Blue

communication issue

What is the IP of the remote site device ?

The linux box has many interfaces, do they all connect to the core switch ?

Can you post the routing table of the linux box ?

Jon

New Member

communication issue

the linux box is having six interfaces

one in 10.x network---connected to core switch

one in 172.18.x network---connected to core switch

one in public network.---connected to core switch

.

one is for cluster-back to back between primary and secondary linux box

one is for ip failover--back to back between primary and secondary linux box

one is unused.

sorry i dont have access to routing table

Regards
Vinayak

Regards Vinayak
Hall of Fame Super Blue

communication issue

Vinayak

It's going to be difficult without knowing the linux routing table. Do you know if it has a default route because i suspect it may be the linux box sending traffic out of the wrong interface.

Jon

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