Seems like Comodo wasn't the only one to change their IP addresses in the past couple days.
Geotrust OCSP: ocsp-gslb.geotrust.net now resolves to 216.168.252.157
Geotrust CRL: tss-geotrust-crl.thawte.com (also known as crl.verisign.net) now resolves to 199.7.71.190