Você deve resolver, adicionando:
MACs=hmac-sha1
ssh -o MACs=hmac-sha1 -vvvl user ip
infelizmente não tenho acesso ao servidor ssh, só vejo:
Platform: i586-pc-linux-gnu
Compiled with: liblua-5.2.3 openssl-1.0.1k libpcre-8.35 libpcap-1.6.2 nmap-libdnet-1.12 ipv6
Compiled without:
Available nsock engines: epoll poll select
ssh -vvvl user ip
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: setup hmac-sha1
debug1: kex: server->client 3des-cbc hmac-sha1 none
debug2: mac_setup: setup hmac-sha1
debug1: kex: client->server 3des-cbc hmac-sha1 none
debug2: bits set: 502/1024
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
Connection closed by IP