On one of the customer's locations I have a linux router that has been working fine for the last 500 days, but since yesterday, the internet from the internal network doesn't work and I can't SSH to the router. Pinging the WAN interface works. When I try to SSH to router it just waits. Running SSH in verbose mode yields the following:
debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048 debug1: identity file /root/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_4.7p1 Debian-12 debug1: match: OpenSSH_4.7p1 Debian-12 pat OpenSSH_4* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-5 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes256-ctr hmac-ripemd160 none debug1: kex: client->server aes256-ctr hmac-ripemd160 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<4096<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
And then it just waits there and nothing happens. The remote side eventually disconnects the connection. I have already instructed people there to restart the router, but it didn't change anything.
What could be the cause of it? How can I fix it? Going there is not possible for me so I will have to talk someone less techy through.