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Trying to Identify Unknown Firewall Traffic

About once or twice a day I am seeing something like this in the any -> any rule from the inside interface:

6|Jun 21 2013|08:05:25
184.106.86.97
5223
10.210.241.21
56987
access-list inside_access_in permitted tcp inside/184.106.86.97(5223) -> WAN/10.210.241.21(56987) hit-cnt 1 first hit

6|Jun 21 2013|08:05:25
10.210.241.21
56987
184.106.86.97
5223
access-list inside_access_in permitted tcp inside/10.210.241.21(56987) -> WAN/184.106.86.97(5223) hit-cnt 1 first hit

None of our network or VLANS use this inside IP range so I'm not clear on how this can be routed in our network or sent out the firewall. I tried doing a search on the 184.106.86.97 and it only comes back to a RackSpace address.

I also did some searching on port 5223 and it seems to be used by Apple/Iphone products.

Right now, our any -> any rule is set to allow on the inside interface because we are still testing restricting outbound access but it will soon be set to deny. I'm just curious where this traffic is coming from and how it's getting out with this IP address.

Anyone familiar with this?

Cyclops3590

is it always to 184.106.86.97 and port 5223? What do you have for a firewall? Do you have a managed switch?

What I'm thinking is have you perform a capture either from the firewall (if its capable) using an ACL to restrict what gets captured or if you have a managed switch you can mirror the firewall traffic to a different switch port, plug a computer into it and sniff the traffic. After it happens again look at the traffic at that time to see if you can spot the protocol being used.

also, maybe via arp table lookups you can find out the MAC of that client. see if its an apple device of some sort. maybe find out if its an iOS device because like you saw 5223 should be something related to apple's push notification

dec0mpile

I think you are on the right track here. Port 5223 is used by Apple primarily for iCloud, but also for MobileMe, APNs, FaceTime, etc. You most likely have users in your company that have their devices connected to your network. When you block the port they will experience connectivity issues (unless they disconnect from the network and use 3G/4G).

I can't explain the rackspace IP, perhaps one of the users has hosted email account or something similar with rackspace on their phone or tablet.

AllDaySentry

ASKER

Yes, the traffic is always to 184.106.86.97 on port 5223. The inside IP changes but its always a 10 address: 10.148.236.144, 10.210.241.21, etc.

We are using a ASA 5510 firewall. We have a 3750 switch that does our internal L3 routing using 172.16.0.0/24 subnets internally and we have one 10.45.0.0/16 subnet.

Its only a couple hits a day and we are going to be setting the any -> any to deny soon but I'm confused how this even gets routed and where it's coming from.

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Cyclops3590

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AllDaySentry

ASKER

I think you are right. Its most likely hairpinning. After reviewing the logs it does not look like any meaningful traffic.