After the operating system is installed on the T3500, remote SSH logins are slow to implement.
According to the fact that local SSH logins are normal, this problem is hardly possible related to the T3500 hardware. The network may be faulty.
Use a normal T3500 onsite to ping the faulty T3500, and the ping is successful. However, pinging the faulty T3500 remotely fails.
After the customer logs in to a normal T3500 using an SSH tool, the customer successfully pings the faulty device from the normal T3500. This fact indicates an error on the transition between the Intranet and Internet.
Compare a normal T3500 with the faulty T3500 in terms of the IP address, subnet mask, and gateway address. It is found that the gateway address and IP address of the faulty T3500 resided on different network segments. External access to the T3500 passes through improper routing; therefore, logins slow down and pings fail.
Configure the gateway address to the same network segment as the IP address.