# Problem Routing SLES 11 SP3 **URL:** \ **Category:** SLES Networking\ **Created:** [September 6, 2016, 10:42am UTC](https://forums.suse.com/t/problem-routing-sles-11-sp3/28609 "2016-09-06T10:42:06Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![duvenbeck](https://avatars.discourse-cdn.com/v4/letter/d/e0b2c6/32.png) [@duvenbeck](https://forums.suse.com/u/duvenbeck)\ **Post date:** [September 6, 2016, 10:42am UTC](https://forums.suse.com/t/problem-routing-sles-11-sp3/28609/1 "2016-09-06T10:42:06Z")
Hello, i have a strange routing problem under SLES 11 SP3. I have the following network interface settings: eth1 Link encap:Ethernet HWaddr AC:16:2D:6F:7E:F1 inet addr:192.168.10.56 Bcast:192.168.10.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1952841 errors:0 dropped:5520 overruns:0 frame:0 TX packets:587477 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:522637737 (498.4 Mb) TX bytes:793376827 (756.6 Mb) Interrupt:37 And these Routing Table: Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.10.250 0.0.0.0 UG 0 0 0 eth1 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 The 192.168.10.250 is our default Gateway for the whole network. There are more than 500 Hosts using these Gateway. Only on these Server SLES Server I have a problem to reach some networks. Some IP`s work, some doesn`t work. Here an example traceroute to an IP Addresses in our Subnet 192.168.8.0/24 Working correct: traceroute to 192.168.8.170 (192.168.8.170), 30 hops max, 40 byte packets using UDP 1 192.168.10.250 (192.168.10.250) 0.359 ms 0.116 ms 0.088 ms 2 192.168.8.170 (192.168.8.170) 2.545 ms \* \* Not Working: traceroute to 192.168.8.62 (192.168.8.62), 30 hops max, 40 byte packets using UD P 1 \* \* \* 2 \* \* \* 3 \* \* \* 4 \* \* \* 5 \* \* \* 6 \* \* \* 7 \* \* \* 8 \* \* \* ^C Sometimes some hots work, sometimes they don`t. I also try to use another network interface. I don’t have any idea what causes these problem. Please help me! 😉 Thanks Jörg ---
**Author:** ![duvenbeck](https://avatars.discourse-cdn.com/v4/letter/d/e0b2c6/32.png) [@duvenbeck](https://forums.suse.com/u/duvenbeck)\ **Post date:** [September 6, 2016, 1:03pm UTC](https://forums.suse.com/t/problem-routing-sles-11-sp3/28609/2 "2016-09-06T13:03:41Z")
Ein ähnliches Problem hatten wir unter einem CENTOS Server. Da hat das hier geholfen. /etc/sysctl.conf # Controls IP packet forwarding net.ipv4.ip\_forward = 1 Unter SLES mit /etc/sysctl.conf # Controls IP packet forwarding net.ipv4.conf.all.forwarding = 1 ändert sich aber nichts am Verhalten ---
**Author:** ![Jens-U](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@Jens-U](https://forums.suse.com/u/Jens-U)\ **Post date:** [September 6, 2016, 8:13pm UTC](https://forums.suse.com/t/problem-routing-sles-11-sp3/28609/3 "2016-09-06T20:13:05Z")
Hi Jörg, have you had a look at the corresponding tcpdump / wireshark output, to see if your box is sending proper ICMP requests to the correct gateway (check the destination MAC of the ICMP requests). And you may want to take a look at the ARP table of the server, to check for stray entries (whereever these may have come from - if they’re there, we’ll try to find out 😉 ) Regards, J