cms and predictor forward...

Unanswered Question
Aug 4th, 2008
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hi all,

how is possible that i cannot iniziate a connetion from a server farm with predictor forward? it seems stupid from my point of view..below a conf:

serverfarm forward_tmp

no nat server

no nat client

predictor forward

vserver direct_tmp

virtual any

serverfarm forward_tmp


i can ping to (from outside csm and msfc, external router) but i canno ping from ip (that is a linux server with correct route table...) to router above mentioned.

may you help me?

thx das

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Overall Rating: 2.3 (5 ratings)
danilodicesare Mon, 08/04/2008 - 06:12
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PS: debug command below


sessionID:0x1fffee sessionID_Seq:0x15d vserverID:0x2 RLID:0x7ff9

DST IP: SRC IP: Enacps:0x7ff4

03:43:24: CSM2:

LB: TYPE:1 LENGTH:128 CNTR:0x6b SEQ:0x15d ID:0x1fffee

L7 COMMAND: Dest-Decision Cmd

sessionID:0x1fffee sessionID_Seq:0x15d

Failed LB : access-denied

Syed Iftekhar Ahmed Mon, 08/04/2008 - 11:17
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Use the following config

vserver direct_tmp

virtual any

serverfarm forward_tmp



danilodicesare Mon, 08/04/2008 - 11:36
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tnx....but why???

i've done it before but i cannot understand why...


Syed Iftekhar Ahmed Mon, 08/04/2008 - 12:04
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If you use a virtual server with ip then CSM will reply the ARP requests for this IP.

How will CSM send a request to the same Real server ip if it is the local address?


sachinga.hcl Mon, 08/04/2008 - 12:31
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To specify the load-balancing algorithm for the server farm, use the predictor command in the SLB serverfarm configuration submode.

Predictor forward tells the CSM to forward traffic in accordance with its internal

routing tables.

In general the contents are retrieved from cache.For transparent caching mode to retrieve content from the origin server use

virtual any

If the CSM is configured in bridge mode. The client VLAN and server VLAN share the same IP address. The same virtual IP address is also configured on the CSM and on the SSLM.

If you do not want NAT to servers in the server farm, use the

no nat server

command in SLB serverfarm configuration submode.

This means this is a transparent redirect so do not change the destination IP address(request toward the server).

The load balance packet IP will not be changed

Similarly if no nat client is configured, the client IP address

in load-balanced packets are not changed

No nat client

Note that the nat server command has no effect when predictor forward is configured, because no servers can be configured.the routing table is used for forwarding.

Hope thisa may help you understand your configuratin.

If you find it useful please add your rating.

Sachin Garg


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