Not sure if this is the correct forum for this, but my web site is being hit with a lot of suspicious entries. Every day, I get a lot of hits where the User Agent is always "Mozilla/4.0 (compatible; Synapse)". They are almost always from different IP addresses, and all are from suspicious countries. The querystring almost always contans a "-1", such as: "n=-1%27"
I've blocked all requests that contain the above user agent, but am worried that there may be legitimate attempts with this browser. 
Can anyone shed any light on what this is?
Here is the ip/country list that I received today:
94.242.233.18 LUXEMBOURG 113.190.144.108 VIET NAM 178.172.155.72 BELARUS 46.211.135.136 UKRAINE 189.19.71.199 BRAZIL 92.112.184.203 UKRAINE 78.170.163.154 TURKEY 176.112.22.5 UKRAINE 41.79.248.174 SOUTH AFRICA 93.84.18.164 BELARUS 175.137.64.125 MALAYSIA 178.129.63.200 RUSSIAN ...

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