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New Member

IOS SLB - Bet I'm doing something stupid - pls enlighten

Hi,

In trying to get SLB to work I believe I'm missing something I imagine is quite basic but i don't know what it is. The short description of my problem is that traffic is not sent back to the client when establishing a connection via the VIP.

I'm using base equipment: a Cat6509 with a Sup-1a, PFC, and MSFC. It's running 12.1(23) so it should be okay. I have a plain vanilla config:

<...snip...>

ip slb serverfarm FARM.100

real 10.33.10.105

inservice

!

real 10.33.10.106

inservice

!

ip slb vserver EBUSINESSCRP

virtual 111.222.222.111 tcp 0

serverfarm FARM.100

inservice

<...snip...>

I have not defined a Vlan for the VIP - didn't work when i did, and can't see why it is necessary(?)

All the show cmds look good except the sh ip slb reals which has the .106 server in READY_TO_TEST state.

I can ping the VIP

I can telnet (on the required port) to the reals

I cannot telnet to the VIP

- sh ip slb conns tells me there is a connection

- tcpdump on the real servers shows the inbound but no outbound traffic, unlike when I tcpdump while connecting to the real. It leads me to think there might be some issue with the RedHat servers but saying so just results in multilateral finger pointing. The svrs have NICs on several VLANs but their default gateways are on the real srvrs VLAN - 10.33.10.x

- debug ip slb all ... well here's a snippit:

<...snip...>

Oct 5 18:20:15: client= 10.0.0.49:1894

Oct 5 18:20:16: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= INIT -> SYNCLIENT

Oct 5 18:20:16: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:16: client= 10.0.0.49:1895

Oct 5 18:20:16: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:16: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:16: client= 10.0.0.49:1895

Oct 5 18:20:16: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:16: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:16: client= 10.0.0.49:1895

Oct 5 18:20:16: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:16: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:16: client= 10.0.0.49:1895

Oct 5 18:20:16: SLB_REAL_DEBUG: 10.33.10.105 (FARM.DBCRP-31) event = SLB_CONN_FAIL state= OPERATIONAL -> OPERATIONAL

Oct 5 18:20:16: SLB_CONN_DEBUG: TCP event= DESTROY, state= SYNCLIENT -> ZOMBIE

Oct 5 18:20:16: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:16: client= 10.0.0.49:1895

Oct 5 18:20:19: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= INIT -> SYNCLIENT

Oct 5 18:20:19: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:19: client= 10.0.0.49:1895

Oct 5 18:20:19: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:19: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:19: client= 10.0.0.49:1895

Oct 5 18:20:19: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:19: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:19: client= 10.0.0.49:1895

Oct 5 18:20:19: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= SYNCLIENT -> SYNCLIENT

Oct 5 18:20:19: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:19: client= 10.0.0.49:1895

Oct 5 18:20:19: SLB_REAL_DEBUG: 10.33.10.105 (FARM.DBCRP-31) event = SLB_CONN_FAIL state= OPERATIONAL -> OPERATIONAL

Oct 5 18:20:19: SLB_CONN_DEBUG: TCP event= DESTROY, state= SYNCLIENT -> ZOMBIE

Oct 5 18:20:19: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

Oct 5 18:20:19: client= 10.0.0.49:1895

Oct 5 18:20:25: SLB_CONN_DEBUG: TCP event= SYN_CLIENT, state= INIT -> SYNCLIENT

Oct 5 18:20:25: v_ip= 111.222.222.111:13515 ( 8), real= 10.33.10.105

<...snip...>

Thx for any help given

Mike

  • Application Networking
2 REPLIES
Cisco Employee

Re: IOS SLB - Bet I'm doing something stupid - pls enlighten

Mike,

could you try to do the following :

conf t

ip slb serverfarm FARM.100

nat server

this will tell the MSFC to nat the vip address into the server ip address.

Regards,

Gilles.

Thanks for rating this answer.

New Member

Re: IOS SLB - Bet I'm doing something stupid - pls enlighten

Thanks Gilles - that seems to have done the trick, I can now telnet to the VIP on the required port and connections are established with the round robin working and all.

I was right ... i was had missed something basic!

Thanks again, problem solved

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