Ubuntu
在 Ubuntu 上緩慢連接 ssh
我最近在我的桌面上安裝了 Ubuntu 10.10 作為第二個作業系統,但我遇到了一個奇怪的問題:通過 ssh 連接到其他 linux 機器需要幾十秒。在 Windows 上,我沒有這樣的問題,它立即連接。
所以,同樣,這不是主機的問題(即高負載),也沒有連接問題(即高延遲、丟包等)。問題肯定與客戶端及其在連接時執行的操作有關。
我懷疑這與 DNS/反向 DNS 有關。就像在連接之前等待在我的 IP 上獲得反向 DNS 一樣,我不知道..
有誰知道如何解決這一問題?謝謝。
稍後編輯:正如 Janne 建議的那樣,我使用 -vvv 參數執行命令。輸出是:
ssh -p 6969 -vvv myuser@myserver.mydomain.com OpenSSH_5.5p1 Debian-4ubuntu4, OpenSSL 0.9.8o 01 Jun 2010 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to myserver.mydomain.com [178.21.120.198] port 6969. debug1: Connection established. debug1: identity file /home/sorin/.ssh/id_rsa type -1 debug1: identity file /home/sorin/.ssh/id_rsa-cert type -1 debug1: identity file /home/sorin/.ssh/id_dsa type -1 debug1: identity file /home/sorin/.ssh/id_dsa-cert type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3 debug1: match: OpenSSH_4.3 pat OpenSSH_4* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu4 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 none debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug2: dh_gen_key: priv key bits set: 111/256 debug2: bits set: 534/1024 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug3: put_host_port: [178.21.120.198]:6969 debug3: put_host_port: [myserver.mydomain.com]:6969 debug3: check_host_in_hostfile: host [myserver.mydomain.com]:6969 filename /home/sorin/.ssh/known_hosts debug3: check_host_in_hostfile: host [myserver.mydomain.com]:6969 filename /home/sorin/.ssh/known_hosts debug3: check_host_in_hostfile: match line 1 debug3: check_host_in_hostfile: host [178.21.120.198]:6969 filename /home/sorin/.ssh/known_hosts debug3: check_host_in_hostfile: host [178.21.120.198]:6969 filename /home/sorin/.ssh/known_hosts debug3: check_host_in_hostfile: match line 2 debug1: Host '[myserver.mydomain.com]:6969' is known and matches the RSA host key. debug1: Found key in /home/sorin/.ssh/known_hosts:1 debug2: bits set: 491/1024 debug1: ssh_rsa_verify: signature correct debug2: kex_derive_keys debug2: set_newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug2: set_newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /home/sorin/.ssh/id_rsa ((nil)) debug2: key: /home/sorin/.ssh/id_dsa ((nil)) debug1: Authentications that can continue: publickey,gssapi-with-mic,password debug3: start over, passed a different list publickey,gssapi-with-mic,password debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password debug3: authmethod_lookup gssapi-with-mic debug3: remaining preferred: publickey,keyboard-interactive,password debug3: authmethod_is_enabled gssapi-with-mic debug1: Next authentication method: gssapi-with-mic debug1: Unspecified GSS failure. Minor code may provide more information Credentials cache file '/tmp/krb5cc_1000' not found debug1: Unspecified GSS failure. Minor code may provide more information Credentials cache file '/tmp/krb5cc_1000' not found debug1: Unspecified GSS failure. Minor code may provide more information debug2: we did not send a packet, disable method debug3: authmethod_lookup publickey debug3: remaining preferred: keyboard-interactive,password debug3: authmethod_is_enabled publickey debug1: Next authentication method: publickey debug1: Trying private key: /home/sorin/.ssh/id_rsa debug3: no such identity: /home/sorin/.ssh/id_rsa debug1: Trying private key: /home/sorin/.ssh/id_dsa debug3: no such identity: /home/sorin/.ssh/id_dsa debug2: we did not send a packet, disable method debug3: authmethod_lookup password debug3: remaining preferred: ,password debug3: authmethod_is_enabled password debug1: Next authentication method: password myuser@myserver.mydomain.com's password:
出於安全原因,我已將使用者替換為 myuser,並將伺服器名稱替換為 myserver.mydomain.com。
嘗試在 sshd_config 和 ssh_config 中將 UseDNS 設置為“no”。還將 GSSAPIAuthentication 設置為 no。
哪一步慢?GSS 認證?您可以通過安裝 moreutils 並執行來為我們提供時間戳
ssh -vvv user@host 2> >(ts)
您可以使用此標誌跳過 GSSAPI:
-o PreferredAuthentications=hostbased,publickey,keyboard-interactive,password