'ping git-scm.com' retorna 'ping: host desconhecido git-scm.com'

Question

Desde há alguns dias atrás, não consigo aceder a git-scm.com e ao tentar ping ao domínio:

ping git-scm.com

Eu recebo um:

ping: unknown host git-scm.com

Como posso verificar se há erros nos arquivos de configuração do meu sistema? Estou executando o SO elementar , que é baseado em Ubuntu 12.04 e parece ser o único domínio com problemas de acesso.

Conteúdo de /etc/resolv.conf :

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1
search fibertel.com.ar

("fibertel" é meu provedor de ISP)

Aqui está a saída de dig git-scm.com +trace :

; <<>> DiG 9.8.1-P1 <<>> git-scm.com +trace
;; global options: +cmd
.           317238  IN  NS  k.root-servers.net.
.           317238  IN  NS  l.root-servers.net.
.           317238  IN  NS  m.root-servers.net.
.           317238  IN  NS  a.root-servers.net.
.           317238  IN  NS  b.root-servers.net.
.           317238  IN  NS  c.root-servers.net.
.           317238  IN  NS  d.root-servers.net.
.           317238  IN  NS  e.root-servers.net.
.           317238  IN  NS  f.root-servers.net.
.           317238  IN  NS  g.root-servers.net.
.           317238  IN  NS  h.root-servers.net.
.           317238  IN  NS  i.root-servers.net.
.           317238  IN  NS  j.root-servers.net.
;; Received 500 bytes from 127.0.0.1#53(127.0.0.1) in 254 ms

com.            172800  IN  NS  m.gtld-servers.net.
com.            172800  IN  NS  l.gtld-servers.net.
com.            172800  IN  NS  k.gtld-servers.net.
com.            172800  IN  NS  j.gtld-servers.net.
com.            172800  IN  NS  i.gtld-servers.net.
com.            172800  IN  NS  h.gtld-servers.net.
com.            172800  IN  NS  g.gtld-servers.net.
com.            172800  IN  NS  f.gtld-servers.net.
com.            172800  IN  NS  e.gtld-servers.net.
com.            172800  IN  NS  d.gtld-servers.net.
com.            172800  IN  NS  c.gtld-servers.net.
com.            172800  IN  NS  b.gtld-servers.net.
com.            172800  IN  NS  a.gtld-servers.net.
;; Received 489 bytes from 198.41.0.4#53(198.41.0.4) in 525 ms

git-scm.com.        172800  IN  NS  ns1.iwantmyname.net.
git-scm.com.        172800  IN  NS  ns2.iwantmyname.net.
git-scm.com.        172800  IN  NS  ns3.iwantmyname.net.
git-scm.com.        172800  IN  NS  ns4.iwantmyname.net.
;; Received 280 bytes from 192.42.93.30#53(192.42.93.30) in 280 ms

git-scm.com.        3600    IN  A   62.116.130.8
;; Received 45 bytes from 74.208.254.95#53(74.208.254.95) in 241 ms