我在EXSi上，我有两个实例：Ubuntu和CentOS。 这些是networkingconfiguration
Ubuntu的
eth0 Link encap:Ethernet HWaddr 00:50:56:00:1f:68 inet addr:212.83.153.71 Bcast:212.83.153.71 Mask:255.255.255.255 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:76059 errors:0 dropped:26 overruns:0 frame:0 TX packets:7224 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6482760 (6.4 MB) TX bytes:2080684 (2.0 MB) eth1 Link encap:Ethernet HWaddr 00:0c:29:46:5a:f2 inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:252 errors:0 dropped:0 overruns:0 frame:0 TX packets:608 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:42460 (42.4 KB) TX bytes:82474 (82.4 KB) /etc/iptables.conf *nat :PREROUTING ACCEPT [142:12571] :INPUT ACCEPT [5:1076] :OUTPUT ACCEPT [8:496] :POSTROUTING ACCEPT [8:496] -A POSTROUTING -s 192.168.1.0/24 -o eth0 -j MASQUERADE COMMIT *filter :INPUT ACCEPT [2:72] :FORWARD ACCEPT [4:336] :OUTPUT ACCEPT [6:328] -A INPUT -i eth1 -p tcp -j ACCEPT -A INPUT -i eth1 -p udp -j ACCEPT -A INPUT -i eth0 -p tcp --dport ssh -j ACCEPT COMMIT CentOS的
eth0 Link encap:Ethernet HWaddr 00:0C:29:74:1C:55 inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fe74:1c55/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:499 errors:0 dropped:0 overruns:0 frame:0 TX packets:475 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:68326 (66.7 KiB) TX bytes:82641 (80.7 KiB)
主要问题是如果我从CentOS实例执行这个命令
ssh 192.168.1.2
连接需要20多秒。 它似乎是将连接路由到错误的networking。
会是什么呢？ 谢谢！
大多数情况下，SSH连接延迟是由反向DNS查找失败引起的。 尝试以下方法之一来解决问题…
1： /etc/ssh/sshd_config下行添加到/etc/ssh/sshd_config ：
UseDNS no
2：将主机名和IP添加到/etc/hosts
centos 192.168.1.1 ubuntu 192.168.1.2