Following is message with show conn in the pix525,ver 7.0. x.x.x.x is email server ip address. I don't think have 4g email send out in that time. How to understand this message? that source ip address is changed as time.
"TCP out 62.37.236.x:25 in x.x.x.x:28626 idle 0:07:05 bytes 4294967280 flags UO"