We demonstrate an environmentally robust optical frequency comb based on a polarization-maintaining, all-fiber, figure-eight laser. The comb is phase locked to a cavity-stabilized cw laser by use of an intracavity electro-optic phase modulator yielding $1.6\mathrm{MHz}$ feedback bandwidth. This high bandwidth provides close to shot-noise-limited residual phase noise between the comb and cw reference laser of $-94\mathrm{dBc}∕\mathrm{Hz}$ from $20\mathrm{Hz}\text{to}200\mathrm{kHz}$ and an integrated in-loop phase noise of $32\mathrm{mrad}$ from $1\mathrm{Hz}\text{to}1\mathrm{MHz}$ . Moreover, the comb remains phase locked under significant mechanical vibrations of over $1g$ . This level of environmental robustness is an important step toward a fieldable fiber frequency comb.