无法通过SSH进入Vagrant guest

Question

直到最近，我还可以通过SSH连接到我的Vagrant机器，没有任何问题。然而，现在：

$ ssh -vvv vagrant@127.0.0.1 -p 2222 OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g 1 Mar 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug2: resolving "127.0.0.1" port 2222 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to 127.0.0.1 [127.0.0.1] port 2222. debug1: Connection established. debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_rsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_ecdsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_ed25519 type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user1/.ssh/id_ed25519-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 ssh_exchange_identification: read: Connection reset by peer

我检查了客人里的/etc/hosts.allow和/etc/hosts.deny。那里什么都没有。我几乎可以肯定这与有人重写了/etc/resolv.conf的内容有关。现在的内容是:在我可以ping google.com的主机上，网络似乎可以正常工作，但在来宾主机上，我不能这样做。有什么想法吗？