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LinkedIn was only one of thousands of websites that went down on Wednesday due to issues with its domain name system (DNS) servers, according to Cisco.

Although LinkedIn has stated that its outage was due to an error made by the company that manages its domain and not due to any form of malicious activity, there was some malicious activity involved — just not directly aimed at the social networking company.

Network Solutions wrote on its company blog that it had been resolving a distributed denial-of-service (DDoS) attack at the time, and that “a small number of Network Solutions customers were inadvertently affected”.

Looking at the problem from a network perspective, Cisco said it saw the name servers for Network Solutions change to those at ztomy.com.

“For example, the domain usps.com was pointed to the DNS nameservers ns1621.ztomy.com and ns2621.ztomy.com. Yelp had their name servers changed to ns1620.ztomy.com and ns2620.ztomy.com. Fidelity, meanwhile, was pointed at ns1622.ztomy.com and ns2622.ztomy.com.”

However, Cisco believes that this actually lends credibility to the theory that it was not a malicious attack.

“The fact that so many domains were displaced in such a highly visible way supports Network Solutions’ claim that this was indeed a configuration error.”

Including the US Postal Service, Yelp, and Fidelity, Cisco believes that almost 5,000 domains may have been affected. The list includes other major companies, including Subaru, Mazda USA, US Airways, Craigslist, and Weather.com.