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Cisco NAT problem 2821 router

Posted on 2009-07-14
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Last Modified: 2012-05-07
I have cisco 2821 router. I NAT many devices thru it. Occasionally (every 2 days or so) I have 1 device that cannot be accessed from outside, like the NAT is not working. Other devices with static NAT's are working fine at same time. Sh ip nat trans for all devices shows traffic in and out. But for this one device with static NAT, not traffic but NAT shows in place. I do clear ip nat trans *, and still nothing. I remove the static NAT for that device only, then readd it, and it works (for a few more days), then stops again. Have to remove (no ip nat inside source static a.a.a.a b.b.b.b) and then readd it (ip nat inside source static a.a.a.a b.b.b.b) to get it to work again. Any ideas? I am on 12.4.(24) T1 IOS
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Question by:tdiops
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7 Comments
 
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Expert Comment

by:Istvan Kalmar
ID: 24853342
what says the log?
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Expert Comment

by:memo_tnt
ID: 24853752
does it work with router reload ?? before removing the static nat ???
 
will you send run config ,, remove passwords and real IPs
??
 
BR
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by:mikecr
ID: 24855306
Do you have any issues pinging the inside device from the router, such as dropped pings or high ping times?
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by:tdiops
ID: 24855414
no problems after reload of the router...that was how one of the other techs was solving the issue...reboot or clear ip nat trans in middle of busy activity. Only problem is that it killed every other connection thru device. By removing the one nat entry, then reapplying it, router stays up, other devices still work, and then this device now worked. no other issues. I can ping inside on local network, I can ping the router from the device and vice versa, just cannot pass anything thru the router until removing stat nat and reapply.
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by:mikecr
ID: 24855440
Can you post your configuration here so that I can get a look at it? Just remove any passwords or live IP addresses.
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tdiops earned 0 total points
ID: 24908743
I noticed that the router was on 12.3 and I read a forum somewhere where others had issues with NAT on 12.3 versions. Recommended was upgrade to 12.4 IOS. I upgraded and so far no problems. Will report back in it happens again.
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