topic Large sequence numbers on FWSM in Network Security

Large sequence numbers on FWSM

ALIAOF_ — Mon, 11 Mar 2019 22:00:02 GMT

We recently installed a 6509 with FWSM and noticing pretty large sequence numbers like this:

" %FWSM-6-302016: Teardown UDP connection 144551535502653717"

Is that normal?

Large sequence numbers on FWSM

Kureli Sankar — Thu, 08 Dec 2011 21:33:59 GMT

Mohammad,

That may not be the seq. nos used by the end hosts in the connection. It is just a connection ID that the FWSM uses to identify that particular UDP connection. It is sequentially assigned. It is an 8 byte integer made out of xlate ID and sequence counter (4 bytes each). How long has the unit been up? Did you all increase the xlate timeout from the default 3 hours?

-Kureli

Large sequence numbers on FWSM

ALIAOF_ — Thu, 08 Dec 2011 21:51:47 GMT

Thank you for the reply sorry about the wording yes it is the connection ID not the sequence number I said it wrong. Xlate is still default of 3 hours and unit has been up since september 2011.

So the connection ID's that long are normal on FWSM?

Large sequence numbers on FWSM

Kureli Sankar — Thu, 08 Dec 2011 22:02:16 GMT

Yes it is normal. Although this one is a a lot longer than the ones that I see usually .

-Kureli

Large sequence numbers on FWSM

ALIAOF_ — Thu, 08 Dec 2011 22:11:30 GMT

Thank you again so should this be a concern?

Large sequence numbers on FWSM

Kureli Sankar — Thu, 08 Dec 2011 22:16:13 GMT

No. Don't worry about it. Get me the

sh xlate count

sh conn count

output from the FWSM.

-Kureli

Large sequence numbers on FWSM

ALIAOF_ — Thu, 08 Dec 2011 22:43:59 GMT

# show xlate count

355 in use, 1310 most used

# show conn count

215 in use, 365939 most used

Thank you again here is the output.

Large sequence numbers on FWSM

Kureli Sankar — Fri, 09 Dec 2011 16:24:55 GMT

Interesting. So at some point the blade has seen 365939 connections when at present there are only 215.

So, that explains the very high sequential connection ID increase.

-Kureli

Large sequence numbers on FWSM

ALIAOF_ — Fri, 09 Dec 2011 18:00:08 GMT

Ok so once the xlate times out shouldn't the connection ID's get smaller ? or will the device reboot can only accomplish that?

Re: Large sequence numbers on FWSM

Kureli Sankar — Fri, 09 Dec 2011 18:44:52 GMT

Yes. Either a reload or after its hits the maximum decimal integer made up of these 8 bytes(64 bits), I believe 20 digits is hit it will reset back to the smaller number. So according to all 1s 64 digits the max decimal number is

18446744073709551615 (20 digits).

I used this site to convert binary to decimal:

http://www.exploringbinary.com/binary-converter/

-Kureli

Large sequence numbers on FWSM

ALIAOF_ — Fri, 09 Dec 2011 18:51:34 GMT

Thankk you so much for all your help and explaining everything have a great day.