IP_VFR-3-COALESCE_ERROR on 867VAE

[itservicesyd]

Hey!

We keep getting these log messages:

%IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through Vlan1 - datagram 1898 bytes is too big. UDP packet 192.168.200.100:53 -> 31.222.xxx.xx:53 has ident: 21511 flags:0x0 and 2 fragments

Packet size varies between 1800 - 3800. 192.168.200.100 is our internal DNS server.

I see that it can have something to do with an older bugged IOS, but I just upgraded it to c860vae-ipbasek9-mz.153-2.T and still getting the error.

I've also seen a workaround out there to increase huge buffer size but it only fills all the buffers up then, max 16.

Also, as an additional side question:

There is a c860vae-advsecurityk9-mz.153-2.T.bin out for the 867VAE, but it just tells me:

%Warning: File not a valid executable for this system

The file is downloaded from different computers, same result. Checked for available space on flash: and it's good enough.

I'm attaching my running-config + show version in the same file.

Thankful for a reply!

Kind regards

Daniel

[itservicesyd]

Just had to add. We have problems with our Internet going down (at least DNS resolve) as well, and it does seem to correlate with these messages.

[InayathUlla Sharieff]

HI Daniel,

Please give it a try with the below action plan.

Recommended Action Plan:

1. no ip virtual-reassembly
2.  Increase the max-reassembly and max-fragment size as per the values assigned below:
Router(config)# interface vlan 1
ip virtual-reassembly [max-reassemblies number] [max-fragments number]

Let me know if this helps.

Regards

Inayath

[itservicesyd]

I'll give it a try over the day and report back, thanks

[itservicesyd]

Ok, I set:

buffers huge size 30000 (just a high figure for the sake of it)

no ip virtual-reassembly

ip virtual-reassembly max-reassemblies 64

Still getting the same error message - unable to coalesce....

I know that it's big because it's probably DNSSEC, but why do I get an error from it.... ugh.

[Reza Sharifi]

Hi.

Looking at your config I see:

ip nat inside source list 1 interface ATM0.1 overload

The inside interface should be vlan 1

ip nat inside source list 1 interface vlan1 overload

HTH

[itservicesyd]

Are you sure? If I use "ip nat inside source list 1 interface vlan1 overload" the Internet doesn't work. All guides I've read says that the ATM interface should have this command attached to it for NAT to work.