Modern Shipboard Defenses

I admit, I'm not to knowledgeable about this. Hopefully some of the members here can give us some information about how a large sized ship defends itself against the new generation Mach 3+ cruise missiles.

One thing I cant understand, is when you have an active seeker on a missile flying that fast at low altitude, the nose cone has to be of a metal or ceramic design to withstand the scorching temperatures. And that negates a radar homing design, or so I would figure. I guess you could use an IR or optical style seeker [using quartz glass?], but that is highly susceptible to jamming and decoys. Even a laser beam at a moderate power will burn it out.

Your thoughts?

The way I see it - both the supersonic anti-ship and anti-missile rockets have no problems flying for quite a time on mach 2-3 at low level. The Russian AS-15 Kickback does even Mach 5, though at altitudes in excess of 35000 ft. The nose cone can withstand that, as you've noted it's made the radio-transparent material, come sort of composite ceramics.
The IR guiding systems have their advantages, they're passive, so the attacked ship cannot detect, via it's ESM (electronics support measures, basically a RWR) it is attacked. I'm not sure that IR countermeasures are more efficient than the RF countermeasures.

The defense should have a tough time to deal with the supersonic A/S misiles, compared against the sub-sonic ones, but it is not an impossible job. Some 20 years ago the USN tested the RIM-116 vs. the 'Vandal', the mach 2+ target missile, with direct hits registered.
Nowadays, the navies are testing the laser-based defenses.

The Laser went active on a US Navy ship floating around in the middle east..Navy Tests Super Precise Laser Weapon in Persian Gulf - Defense One