I currently have a 7604 that every 4 hours when the ARP cache clears my network looses connectivity for 8 minutes and then the table starts to populate once again.

Cisco Internetwork Operating System Software
IOS (tm) s3223_rp Software (s3223_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(18)SXF15, RELEASE SOFTWARE (fc1)
Technical Support:
Copyright (c) 1986-2008 by cisco Systems, Inc.
Compiled Fri 29-Aug-08 19:09 by kellythw
Image text-base: 0x40101040, data-base: 0x42D738D0

ROM: System Bootstrap, Version 12.2(17r)SX3, RELEASE SOFTWARE (fc1)
BOOTLDR: s3223_rp Software (s3223_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(18)SXF15, RELEASE SOFTWARE (fc1)

ROUTER7604 uptime is 7 weeks, 1 day, 3 hours, 17 minutes
Time since ICONBRICKEL.7604 switched to active is 7 weeks, 1 day, 3 hours, 16 minutes
System returned to ROM by s/w reset (SP by power-on)
System restarted at 13:50:01 EST Thu Sep 18 2008
System image file is "sup-bootdisk:s3223-advipservicesk9_wan-mz.122-18.SXF15.bin"

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cisco CISCO7604 (R7000) processor (revision 2.0) with 458752K/65536K bytes of memory.
Processor board ID FOX1202GFHW
R7000 CPU at 300Mhz, Implementation 0x27, Rev 3.3, 256KB L2, 1024KB L3 Cache
Last reset from power-on
SuperLAT software (copyright 1990 by Meridian Technology Corp).
X.25 software, Version 3.0.0.
Bridging software.
TN3270 Emulation software.
7 Virtual Ethernet/IEEE 802.3 interfaces
57 Gigabit Ethernet/IEEE 802.3 interfaces
1915K bytes of non-volatile configuration memory.

65536K bytes of Flash internal SIMM (Sector size 512K).
Configuration register is 0x2102
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TAMSCODANConnect With a Mentor Author Commented:
I found that the CISCO was not blocking the  ARP, it was an upstream device blocking it. Thank you all.
The X here represents eXperimental release.
Highly suggest updating to more recent 12.2.x.T version
TAMSCODANAuthor Commented:
what is the entire firmware version that you are referring too.
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Sorry, wrong information. I forgot this is a 7604...
There is a new version of yours. Could be bug fixes for yours.
TAMSCODANAuthor Commented:
Do you know for sure if this fixes the ARP issues?
That's hard to tell, but worth a shot.
I would have to know a lot more about your topology and what else you have in the mix that could have proxy arp enabled and sucking the arp entries away from your 7604.
You could always increase the arp timeout. 4 hours is the default timeout period
It is an interface command to increase the timeout
   arp timeout <seconds>
  arp timeout 14400

else, i would open a TAC case to find out what is causing the issue to start with and why it takes 8 minutes for the network to start working again.
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