Question: Snort Rule to alert on an "Outer" IP address

"LICATO, JAMES J via Snort-sigs" <[email protected]>
Newsgroups gmane.comp.security.ids.snort.sigs
Message-ID <PH0PR02MB73171B65466DAF886292D5E9D4149@PH0PR02MB7317.namprd02.prod.outlook.com>
Hi,

I have PCAP files that contain both Inner SIP/DIP IP addresses, as well as, Outer SIP/DIP addresses.

Below is a bogus example Snort Rule I wrote,

alert tcp any any -> any any (content:"|00 11 22 33 44 55|"; sid=9000001; Rev:1;) ###Bogus for illustration purposes

where I am trying to alert on a specific byte pattern.

I would like to further restrict this rule to alert only when my Outer SIP IP address is a specific value.  Something to the effect,

alert tcp 192.168.100.40 any -> any any (content:"|00 11 22 33 44 55|"; sid=9000001; Rev:1;) ###Bogus for illustration purposes

I tired this and it is not alerting as expected.  It only seems to alert if I use an Inner SIP/DIP values.

Any thoughts on what I may be doing wrong and if its even possible for a Snort rule to check an Outer SIP/DIP value?

Thank you,
Jim-

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