I had a client today advise they were unable to send or receive e-mail using Outlook. Upon initial inspection this was the case and Outlook showed as disconnected (using Exchange). There were no other obvious issues, web browsing and all network services “seemed” to be working properly. However, there were frequent pop-ups with the message:
TCP/IP ping command has encountered a problem and needs to close
Pinging did work fine, for the record. While doing a quick search for possible solutions I came across many others with a similar problem, so I thought I would take a moment to post my findings.
The Event logs had additional errors the key one being: Event ID: 4226, Source: Tcpip, TCP/IP has reached the security limit imposed on the number of concurrent TCP connect attempts.
Though there could be other causes, this usually indicates some sort of malware, as confirmed by EventID.net
Kaspersky’s Anti-rootkit utility TDSSKiller located 2 viruses, and AVG a third as shown in the image below. Keep in mind other viruses could present themselves in the same way. Clearing all temp folders and a full scan by multiple other malware detection apps did not reveal any other issues, but one must always be concerned that “once infected, always suspected”. Outlook now worked properly with no repairs required to the application or networking.